gstreamer/ext/theora/gsttheoraenc.c

/* GStreamer
 * Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/**
 * SECTION:element-theoraenc
 * @see_also: theoradec, oggmux
 *
 * This element encodes raw video into a Theora stream.
 * <ulink url="http://www.theora.org/">Theora</ulink> is a royalty-free
 * video codec maintained by the <ulink url="http://www.xiph.org/">Xiph.org
 * Foundation</ulink>, based on the VP3 codec.
 *
 * The theora codec internally only supports encoding of images that are a
 * multiple of 16 pixels in both X and Y direction. It is however perfectly
 * possible to encode images with other dimensions because an arbitrary
 * rectangular cropping region can be set up. This element will automatically
 * set up a correct cropping region if the dimensions are not multiples of 16
 * pixels.
 *
 * To control the quality of the encoding, the #GstTheoraEnc::bitrate and
 * #GstTheoraEnc::quality properties can be used. These two properties are
 * mutualy exclusive. Setting the bitrate property will produce a constant
 * bitrate (CBR) stream while setting the quality property will produce a
 * variable bitrate (VBR) stream.
 *
 * <refsect2>
 * <title>Example pipeline</title>
 * |[
 * gst-launch -v videotestsrc num-buffers=1000 ! theoraenc ! oggmux ! filesink location=videotestsrc.ogg
 * ]| This example pipeline will encode a test video source to theora muxed in an
 * ogg container. Refer to the theoradec documentation to decode the create
 * stream.
 * </refsect2>
 *
 * Last reviewed on 2006-03-01 (0.10.4)
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gsttheoraenc.h"

#include <string.h>
#include <stdlib.h>             /* free */

#include <gst/tag/tag.h>
#include <gst/video/video.h>

#define GST_CAT_DEFAULT theoraenc_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

#define GST_TYPE_BORDER_MODE (gst_border_mode_get_type())
static GType
gst_border_mode_get_type (void)
{
  static GType border_mode_type = 0;
  static const GEnumValue border_mode[] = {
    {BORDER_NONE, "No Border", "none"},
    {BORDER_BLACK, "Black Border", "black"},
    {BORDER_MIRROR, "Mirror image in borders", "mirror"},
    {0, NULL, NULL},
  };

  if (!border_mode_type) {
    border_mode_type =
        g_enum_register_static ("GstTheoraEncBorderMode", border_mode);
  }
  return border_mode_type;
}

#define GST_TYPE_MULTIPASS_MODE (gst_multipass_mode_get_type())
static GType
gst_multipass_mode_get_type (void)
{
  static GType multipass_mode_type = 0;
  static const GEnumValue multipass_mode[] = {
    {MULTIPASS_MODE_SINGLE_PASS, "Single pass", "single-pass"},
    {MULTIPASS_MODE_FIRST_PASS, "First pass", "first-pass"},
    {MULTIPASS_MODE_SECOND_PASS, "Second pass", "second-pass"},
    {0, NULL, NULL},
  };

  if (!multipass_mode_type) {
    multipass_mode_type =
        g_enum_register_static ("GstTheoraEncMultipassMode", multipass_mode);
  }
  return multipass_mode_type;
}

/* taken from theora/lib/toplevel.c */
static int
_ilog (unsigned int v)
{
  int ret = 0;

  while (v) {
    ret++;
    v >>= 1;
  }
  return (ret);
}

#define THEORA_DEF_BITRATE              0
#define THEORA_DEF_QUALITY              48
#define THEORA_DEF_KEYFRAME_AUTO        TRUE
#define THEORA_DEF_KEYFRAME_FREQ        64
#define THEORA_DEF_KEYFRAME_FREQ_FORCE  64
#define THEORA_DEF_SPEEDLEVEL           1
#define THEORA_DEF_VP3_COMPATIBLE       FALSE
#define THEORA_DEF_DROP_FRAMES          TRUE
#define THEORA_DEF_CAP_OVERFLOW         TRUE
#define THEORA_DEF_CAP_UNDERFLOW        FALSE
#define THEORA_DEF_RATE_BUFFER          0
#define THEORA_DEF_MULTIPASS_CACHE_FILE NULL
#define THEORA_DEF_MULTIPASS_MODE       MULTIPASS_MODE_SINGLE_PASS
enum
{
  PROP_0,
  PROP_CENTER,
  PROP_BORDER,
  PROP_BITRATE,
  PROP_QUALITY,
  PROP_QUICK,
  PROP_KEYFRAME_AUTO,
  PROP_KEYFRAME_FREQ,
  PROP_KEYFRAME_FREQ_FORCE,
  PROP_KEYFRAME_THRESHOLD,
  PROP_KEYFRAME_MINDISTANCE,
  PROP_NOISE_SENSITIVITY,
  PROP_SHARPNESS,
  PROP_SPEEDLEVEL,
  PROP_VP3_COMPATIBLE,
  PROP_DROP_FRAMES,
  PROP_CAP_OVERFLOW,
  PROP_CAP_UNDERFLOW,
  PROP_RATE_BUFFER,
  PROP_MULTIPASS_CACHE_FILE,
  PROP_MULTIPASS_MODE
      /* FILL ME */
};

/* this function does a straight granulepos -> timestamp conversion */
static GstClockTime
granulepos_to_timestamp (GstTheoraEnc * theoraenc, ogg_int64_t granulepos)
{
  guint64 iframe, pframe;
  int shift = theoraenc->info.keyframe_granule_shift;

  if (granulepos < 0)
    return GST_CLOCK_TIME_NONE;

  iframe = granulepos >> shift;
  pframe = granulepos - (iframe << shift);

  /* num and den are 32 bit, so we can safely multiply with GST_SECOND */
  return gst_util_uint64_scale ((guint64) (iframe + pframe),
      GST_SECOND * theoraenc->info.fps_denominator,
      theoraenc->info.fps_numerator);
}

/* Generate a dummy encoder context for use in th_encode_ctl queries
   Release with th_encode_free()
   This and the next routine from theora/examples/libtheora_info.c */
static th_enc_ctx *
dummy_encode_ctx (void)
{
  th_enc_ctx *ctx;
  th_info info;

  /* set the minimal video parameters */
  th_info_init (&info);
  info.frame_width = 320;
  info.frame_height = 240;
  info.fps_numerator = 1;
  info.fps_denominator = 1;

  /* allocate and initialize a context object */
  ctx = th_encode_alloc (&info);
  if (!ctx)
    GST_WARNING ("Failed to allocate dummy encoder context.");

  /* clear the info struct */
  th_info_clear (&info);

  return ctx;
}

/* Query the current and maximum values for the 'speed level' setting.
   This can be used to ask the encoder to trade off encoding quality
   vs. performance cost, for example to adapt to realtime constraints. */
static int
check_speed_level (th_enc_ctx * ctx, int *current, int *max)
{
  int ret;

  /* query the current speed level */
  ret = th_encode_ctl (ctx, TH_ENCCTL_GET_SPLEVEL, current, sizeof (int));
  if (ret) {
    GST_WARNING ("Error %d getting current speed level.", ret);
    return ret;
  }
  /* query the maximum speed level, which varies by encoder version */
  ret = th_encode_ctl (ctx, TH_ENCCTL_GET_SPLEVEL_MAX, max, sizeof (int));
  if (ret) {
    GST_WARNING ("Error %d getting maximum speed level.", ret);
    return ret;
  }

  return 0;
}

static GstStaticPadTemplate theora_enc_sink_factory =
GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-raw-yuv, "
        "format = (fourcc) { I420, Y42B, Y444 }, "
        "framerate = (fraction) [1/MAX, MAX], "
        "width = (int) [ 1, MAX ], " "height = (int) [ 1, MAX ]")
    );

static GstStaticPadTemplate theora_enc_src_factory =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/x-theora")
    );

#define gst_theora_enc_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstTheoraEnc, gst_theora_enc,
    GST_TYPE_ELEMENT, G_IMPLEMENT_INTERFACE (GST_TYPE_PRESET, NULL));

static gboolean theora_enc_sink_event (GstPad * pad, GstEvent * event);
static gboolean theora_enc_src_event (GstPad * pad, GstEvent * event);
static GstFlowReturn theora_enc_chain (GstPad * pad, GstBuffer * buffer);
static GstStateChangeReturn theora_enc_change_state (GstElement * element,
    GstStateChange transition);
static GstCaps *theora_enc_sink_getcaps (GstPad * pad);
static gboolean theora_enc_sink_setcaps (GstPad * pad, GstCaps * caps);
static void theora_enc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);
static void theora_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void theora_enc_finalize (GObject * object);

static gboolean theora_enc_write_multipass_cache (GstTheoraEnc * enc,
    gboolean begin, gboolean eos);

static void
gst_theora_enc_class_init (GstTheoraEncClass * klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;
  GstElementClass *gstelement_class = GST_ELEMENT_CLASS (klass);

  /* query runtime encoder properties */
  th_enc_ctx *th_ctx;
  int default_speed_level = THEORA_DEF_SPEEDLEVEL;
  int max_speed_level = default_speed_level;

  GST_DEBUG_CATEGORY_INIT (theoraenc_debug, "theoraenc", 0, "Theora encoder");

  th_ctx = dummy_encode_ctx ();
  if (th_ctx) {
    if (!check_speed_level (th_ctx, &default_speed_level, &max_speed_level))
      GST_WARNING
          ("Failed to determine settings for the speed-level property.");
    th_encode_free (th_ctx);
  }

  gobject_class->set_property = theora_enc_set_property;
  gobject_class->get_property = theora_enc_get_property;
  gobject_class->finalize = theora_enc_finalize;

  g_object_class_install_property (gobject_class, PROP_CENTER,
      g_param_spec_boolean ("center", "Center",
          "ignored and kept for API compat only", TRUE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_BORDER,
      g_param_spec_enum ("border", "Border",
          "ignored and kept for API compat only",
          GST_TYPE_BORDER_MODE, BORDER_BLACK,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  /* general encoding stream options */
  g_object_class_install_property (gobject_class, PROP_BITRATE,
      g_param_spec_int ("bitrate", "Bitrate", "Compressed video bitrate (kbps)",
          0, (1 << 24) - 1, THEORA_DEF_BITRATE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
          GST_PARAM_MUTABLE_PLAYING));
  g_object_class_install_property (gobject_class, PROP_QUALITY,
      g_param_spec_int ("quality", "Quality", "Video quality", 0, 63,
          THEORA_DEF_QUALITY,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS |
          GST_PARAM_MUTABLE_PLAYING));
  g_object_class_install_property (gobject_class, PROP_QUICK,
      g_param_spec_boolean ("quick", "Quick",
          "ignored and kept for API compat only", TRUE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_KEYFRAME_AUTO,
      g_param_spec_boolean ("keyframe-auto", "Keyframe Auto",
          "Automatic keyframe detection", THEORA_DEF_KEYFRAME_AUTO,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_KEYFRAME_FREQ,
      g_param_spec_int ("keyframe-freq", "Keyframe frequency",
          "Keyframe frequency", 1, 32768, THEORA_DEF_KEYFRAME_FREQ,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_KEYFRAME_FREQ_FORCE,
      g_param_spec_int ("keyframe-force", "Keyframe force",
          "Force keyframe every N frames", 1, 32768,
          THEORA_DEF_KEYFRAME_FREQ_FORCE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_KEYFRAME_THRESHOLD,
      g_param_spec_int ("keyframe-threshold", "Keyframe threshold",
          "ignored and kept for API compat only", 0, 32768, 80,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_KEYFRAME_MINDISTANCE,
      g_param_spec_int ("keyframe-mindistance", "Keyframe mindistance",
          "ignored and kept for API compat only", 1, 32768, 8,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_NOISE_SENSITIVITY,
      g_param_spec_int ("noise-sensitivity", "Noise sensitivity",
          "ignored and kept for API compat only", 0, 32768, 1,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_SHARPNESS,
      g_param_spec_int ("sharpness", "Sharpness",
          "ignored and kept for API compat only", 0, 2, 0,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_SPEEDLEVEL,
      g_param_spec_int ("speed-level", "Speed level",
          "Controls the amount of analysis performed when encoding."
          " Higher values trade compression quality for speed."
          " This property requires libtheora version >= 1.0"
          ", and the maximum value may vary based on encoder version.",
          0, max_speed_level, default_speed_level,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_CONSTRUCT |
          G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_VP3_COMPATIBLE,
      g_param_spec_boolean ("vp3-compatible", "VP3 Compatible",
          "Disables non-VP3 compatible features",
          THEORA_DEF_VP3_COMPATIBLE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_DROP_FRAMES,
      g_param_spec_boolean ("drop-frames", "VP3 Compatible",
          "Allow or disallow frame dropping",
          THEORA_DEF_DROP_FRAMES,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_CAP_OVERFLOW,
      g_param_spec_boolean ("cap-overflow", "VP3 Compatible",
          "Enable capping of bit reservoir overflows",
          THEORA_DEF_CAP_OVERFLOW,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_CAP_UNDERFLOW,
      g_param_spec_boolean ("cap-underflow", "VP3 Compatible",
          "Enable capping of bit reservoir underflows",
          THEORA_DEF_CAP_UNDERFLOW,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_RATE_BUFFER,
      g_param_spec_int ("rate-buffer", "Rate Control Buffer",
          "Sets the size of the rate control buffer, in units of frames.  "
          "The default value of 0 instructs the encoder to automatically "
          "select an appropriate value",
          0, 1000, THEORA_DEF_RATE_BUFFER,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_MULTIPASS_CACHE_FILE,
      g_param_spec_string ("multipass-cache-file", "Multipass Cache File",
          "Multipass cache file", THEORA_DEF_MULTIPASS_CACHE_FILE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
  g_object_class_install_property (gobject_class, PROP_MULTIPASS_MODE,
      g_param_spec_enum ("multipass-mode", "Multipass mode",
          "Single pass or first/second pass", GST_TYPE_MULTIPASS_MODE,
          THEORA_DEF_MULTIPASS_MODE,
          (GParamFlags) G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&theora_enc_src_factory));
  gst_element_class_add_pad_template (gstelement_class,
      gst_static_pad_template_get (&theora_enc_sink_factory));
  gst_element_class_set_details_simple (gstelement_class,
      "Theora video encoder", "Codec/Encoder/Video",
      "encode raw YUV video to a theora stream",
      "Wim Taymans <wim@fluendo.com>");

  gstelement_class->change_state = theora_enc_change_state;
}

static void
gst_theora_enc_init (GstTheoraEnc * enc)
{
  enc->sinkpad =
      gst_pad_new_from_static_template (&theora_enc_sink_factory, "sink");
  gst_pad_set_chain_function (enc->sinkpad, theora_enc_chain);
  gst_pad_set_event_function (enc->sinkpad, theora_enc_sink_event);
  gst_pad_set_getcaps_function (enc->sinkpad, theora_enc_sink_getcaps);
  gst_pad_set_setcaps_function (enc->sinkpad, theora_enc_sink_setcaps);
  gst_element_add_pad (GST_ELEMENT (enc), enc->sinkpad);

  enc->srcpad =
      gst_pad_new_from_static_template (&theora_enc_src_factory, "src");
  gst_pad_set_event_function (enc->srcpad, theora_enc_src_event);
  gst_element_add_pad (GST_ELEMENT (enc), enc->srcpad);

  gst_segment_init (&enc->segment, GST_FORMAT_UNDEFINED);

  enc->video_bitrate = THEORA_DEF_BITRATE;
  enc->video_quality = THEORA_DEF_QUALITY;
  enc->keyframe_auto = THEORA_DEF_KEYFRAME_AUTO;
  enc->keyframe_freq = THEORA_DEF_KEYFRAME_FREQ;
  enc->keyframe_force = THEORA_DEF_KEYFRAME_FREQ_FORCE;

  enc->expected_ts = GST_CLOCK_TIME_NONE;

  /* enc->speed_level is set to the libtheora default by the constructor */
  enc->vp3_compatible = THEORA_DEF_VP3_COMPATIBLE;
  enc->drop_frames = THEORA_DEF_DROP_FRAMES;
  enc->cap_overflow = THEORA_DEF_CAP_OVERFLOW;
  enc->cap_underflow = THEORA_DEF_CAP_UNDERFLOW;
  enc->rate_buffer = THEORA_DEF_RATE_BUFFER;

  enc->multipass_mode = THEORA_DEF_MULTIPASS_MODE;
  enc->multipass_cache_file = THEORA_DEF_MULTIPASS_CACHE_FILE;
}

static void
theora_enc_clear_multipass_cache (GstTheoraEnc * enc)
{
  if (enc->multipass_cache_fd) {
    g_io_channel_shutdown (enc->multipass_cache_fd, TRUE, NULL);
    g_io_channel_unref (enc->multipass_cache_fd);
    enc->multipass_cache_fd = NULL;
  }

  if (enc->multipass_cache_adapter) {
    gst_object_unref (enc->multipass_cache_adapter);
    enc->multipass_cache_adapter = NULL;
  }
}

static void
theora_enc_finalize (GObject * object)
{
  GstTheoraEnc *enc = GST_THEORA_ENC (object);

  GST_DEBUG_OBJECT (enc, "Finalizing");
  if (enc->encoder)
    th_encode_free (enc->encoder);
  th_comment_clear (&enc->comment);
  th_info_clear (&enc->info);
  g_free (enc->multipass_cache_file);

  theora_enc_clear_multipass_cache (enc);

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static void
theora_enc_reset (GstTheoraEnc * enc)
{
  ogg_uint32_t keyframe_force;
  int rate_flags;

  GST_OBJECT_LOCK (enc);
  enc->info.target_bitrate = enc->video_bitrate;
  enc->info.quality = enc->video_quality;
  enc->bitrate_changed = FALSE;
  enc->quality_changed = FALSE;
  GST_OBJECT_UNLOCK (enc);

  if (enc->encoder)
    th_encode_free (enc->encoder);
  enc->encoder = th_encode_alloc (&enc->info);
  /* We ensure this function cannot fail. */
  g_assert (enc->encoder != NULL);
  th_encode_ctl (enc->encoder, TH_ENCCTL_SET_SPLEVEL, &enc->speed_level,
      sizeof (enc->speed_level));
  th_encode_ctl (enc->encoder, TH_ENCCTL_SET_VP3_COMPATIBLE,
      &enc->vp3_compatible, sizeof (enc->vp3_compatible));

  rate_flags = 0;
  if (enc->drop_frames)
    rate_flags |= TH_RATECTL_DROP_FRAMES;
  if (enc->drop_frames)
    rate_flags |= TH_RATECTL_CAP_OVERFLOW;
  if (enc->drop_frames)
    rate_flags |= TH_RATECTL_CAP_UNDERFLOW;
  th_encode_ctl (enc->encoder, TH_ENCCTL_SET_RATE_FLAGS,
      &rate_flags, sizeof (rate_flags));

  if (enc->rate_buffer) {
    th_encode_ctl (enc->encoder, TH_ENCCTL_SET_RATE_BUFFER,
        &enc->rate_buffer, sizeof (enc->rate_buffer));
  } else {
    /* FIXME */
  }

  keyframe_force = enc->keyframe_auto ?
      enc->keyframe_force : enc->keyframe_freq;
  th_encode_ctl (enc->encoder, TH_ENCCTL_SET_KEYFRAME_FREQUENCY_FORCE,
      &keyframe_force, sizeof (keyframe_force));

  /* Get placeholder data */
  if (enc->multipass_cache_fd
      && enc->multipass_mode == MULTIPASS_MODE_FIRST_PASS)
    theora_enc_write_multipass_cache (enc, TRUE, FALSE);
}

static void
theora_enc_clear (GstTheoraEnc * enc)
{
  enc->packetno = 0;
  enc->bytes_out = 0;
  enc->granulepos_offset = 0;
  enc->timestamp_offset = 0;

  enc->next_ts = GST_CLOCK_TIME_NONE;
  enc->next_discont = FALSE;
  enc->expected_ts = GST_CLOCK_TIME_NONE;
}

static char *
theora_enc_get_supported_formats (void)
{
  th_enc_ctx *encoder;
  th_info info;
  struct
  {
    th_pixel_fmt pixelformat;
    const char *fourcc;
  } formats[] = {
    {
    TH_PF_420, "I420"}, {
    TH_PF_422, "Y42B"}, {
    TH_PF_444, "Y444"}
  };
  GString *string = NULL;
  guint i;

  th_info_init (&info);
  info.frame_width = 16;
  info.frame_height = 16;
  info.fps_numerator = 25;
  info.fps_denominator = 1;
  for (i = 0; i < G_N_ELEMENTS (formats); i++) {
    info.pixel_fmt = formats[i].pixelformat;

    encoder = th_encode_alloc (&info);
    if (encoder == NULL)
      continue;

    GST_LOG ("format %s is supported", formats[i].fourcc);
    th_encode_free (encoder);

    if (string == NULL) {
      string = g_string_new (formats[i].fourcc);
    } else {
      g_string_append (string, ", ");
      g_string_append (string, formats[i].fourcc);
    }
  }
  th_info_clear (&info);

  return string == NULL ? NULL : g_string_free (string, FALSE);
}

static GstCaps *
theora_enc_sink_getcaps (GstPad * pad)
{
  GstCaps *caps;
  char *supported_formats, *caps_string;

  supported_formats = theora_enc_get_supported_formats ();
  if (!supported_formats) {
    GST_WARNING ("no supported formats found. Encoder disabled?");
    return gst_caps_new_empty ();
  }

  caps_string = g_strdup_printf ("video/x-raw-yuv, "
      "format = (fourcc) { %s }, "
      "framerate = (fraction) [1/MAX, MAX], "
      "width = (int) [ 1, MAX ], " "height = (int) [ 1, MAX ]",
      supported_formats);
  caps = gst_caps_from_string (caps_string);
  g_free (caps_string);
  g_free (supported_formats);
  GST_DEBUG ("Supported caps: %" GST_PTR_FORMAT, caps);

  return caps;
}

static gboolean
theora_enc_sink_setcaps (GstPad * pad, GstCaps * caps)
{
  GstStructure *structure = gst_caps_get_structure (caps, 0);
  GstTheoraEnc *enc = GST_THEORA_ENC (gst_pad_get_parent (pad));
  guint32 fourcc;
  const GValue *par;
  gint fps_n, fps_d;

  gst_structure_get_fourcc (structure, "format", &fourcc);
  gst_structure_get_int (structure, "width", &enc->width);
  gst_structure_get_int (structure, "height", &enc->height);
  gst_structure_get_fraction (structure, "framerate", &fps_n, &fps_d);
  par = gst_structure_get_value (structure, "pixel-aspect-ratio");

  th_info_clear (&enc->info);
  th_info_init (&enc->info);
  /* Theora has a divisible-by-sixteen restriction for the encoded video size but
   * we can define a picture area using pic_width/pic_height */
  enc->info.frame_width = GST_ROUND_UP_16 (enc->width);
  enc->info.frame_height = GST_ROUND_UP_16 (enc->height);
  enc->info.pic_width = enc->width;
  enc->info.pic_height = enc->height;
  switch (fourcc) {
    case GST_MAKE_FOURCC ('I', '4', '2', '0'):
      enc->info.pixel_fmt = TH_PF_420;
      break;
    case GST_MAKE_FOURCC ('Y', '4', '2', 'B'):
      enc->info.pixel_fmt = TH_PF_422;
      break;
    case GST_MAKE_FOURCC ('Y', '4', '4', '4'):
      enc->info.pixel_fmt = TH_PF_444;
      break;
    default:
      g_assert_not_reached ();
  }

  enc->info.fps_numerator = enc->fps_n = fps_n;
  enc->info.fps_denominator = enc->fps_d = fps_d;
  if (par) {
    enc->info.aspect_numerator = gst_value_get_fraction_numerator (par);
    enc->info.aspect_denominator = gst_value_get_fraction_denominator (par);
  } else {
    /* setting them to 0 indicates that the decoder can chose a good aspect
     * ratio, defaulting to 1/1 */
    enc->info.aspect_numerator = 0;
    enc->info.aspect_denominator = 0;
  }

  enc->info.colorspace = TH_CS_UNSPECIFIED;

  /* as done in theora */
  enc->info.keyframe_granule_shift = _ilog (enc->keyframe_force - 1);
  GST_DEBUG_OBJECT (enc,
      "keyframe_frequency_force is %d, granule shift is %d",
      enc->keyframe_force, enc->info.keyframe_granule_shift);

  theora_enc_reset (enc);
  enc->initialised = TRUE;

  gst_object_unref (enc);

  return TRUE;
}

static guint64
granulepos_add (guint64 granulepos, guint64 addend, gint shift)
{
  guint64 iframe, pframe;

  iframe = granulepos >> shift;
  pframe = granulepos - (iframe << shift);
  iframe += addend;

  return (iframe << shift) + pframe;
}

/* prepare a buffer for transmission by passing data through libtheora */
static GstFlowReturn
theora_buffer_from_packet (GstTheoraEnc * enc, ogg_packet * packet,
    GstClockTime timestamp, GstClockTime running_time,
    GstClockTime duration, GstBuffer ** buffer)
{
  GstBuffer *buf;
  GstFlowReturn ret = GST_FLOW_OK;

  buf = gst_buffer_new_and_alloc (packet->bytes);
  if (!buf) {
    GST_WARNING_OBJECT (enc, "Could not allocate buffer");
    ret = GST_FLOW_ERROR;
    goto done;
  }

  gst_buffer_fill (buf, 0, packet->packet, packet->bytes);
  gst_buffer_set_caps (buf, GST_PAD_CAPS (enc->srcpad));
  /* see ext/ogg/README; OFFSET_END takes "our" granulepos, OFFSET its
   * time representation */
  GST_BUFFER_OFFSET_END (buf) =
      granulepos_add (packet->granulepos, enc->granulepos_offset,
      enc->info.keyframe_granule_shift);
  GST_BUFFER_OFFSET (buf) = granulepos_to_timestamp (enc,
      GST_BUFFER_OFFSET_END (buf));

  GST_BUFFER_TIMESTAMP (buf) = timestamp;
  GST_BUFFER_DURATION (buf) = duration;

  if (enc->next_discont) {
    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT);
    enc->next_discont = FALSE;
  }

  /* the second most significant bit of the first data byte is cleared
   * for keyframes */
  if (packet->bytes > 0 && (packet->packet[0] & 0x40) == 0) {
    GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_DELTA_UNIT);
  } else {
    GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DELTA_UNIT);
  }
  enc->packetno++;

done:
  *buffer = buf;
  return ret;
}

/* push out the buffer and do internal bookkeeping */
static GstFlowReturn
theora_push_buffer (GstTheoraEnc * enc, GstBuffer * buffer)
{
  GstFlowReturn ret;

  enc->bytes_out += gst_buffer_get_size (buffer);

  ret = gst_pad_push (enc->srcpad, buffer);

  return ret;
}

static GstFlowReturn
theora_push_packet (GstTheoraEnc * enc, ogg_packet * packet,
    GstClockTime timestamp, GstClockTime running_time, GstClockTime duration)
{
  GstBuffer *buf;
  GstFlowReturn ret;

  ret =
      theora_buffer_from_packet (enc, packet, timestamp, running_time, duration,
      &buf);
  if (ret == GST_FLOW_OK)
    ret = theora_push_buffer (enc, buf);

  return ret;
}

static GstCaps *
theora_set_header_on_caps (GstCaps * caps, GSList * buffers)
{
  GstStructure *structure;
  GValue array = { 0 };
  GValue value = { 0 };
  GstBuffer *buffer;
  GSList *walk;

  caps = gst_caps_make_writable (caps);
  structure = gst_caps_get_structure (caps, 0);

  /* put copies of the buffers in a fixed list */
  g_value_init (&array, GST_TYPE_ARRAY);

  for (walk = buffers; walk; walk = walk->next) {
    buffer = walk->data;

    /* mark buffer */
    GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_IN_CAPS);

    /* Copy buffer, because we can't use the original -
     * it creates a circular refcount with the caps<->buffers */
    buffer = gst_buffer_copy (buffer);

    g_value_init (&value, GST_TYPE_BUFFER);
    gst_value_set_buffer (&value, buffer);
    gst_value_array_append_value (&array, &value);
    g_value_unset (&value);

    /* Unref our copy */
    gst_buffer_unref (buffer);
  }

  gst_structure_set_value (structure, "streamheader", &array);
  g_value_unset (&array);

  return caps;
}

static void
theora_enc_force_keyframe (GstTheoraEnc * enc)
{
  GstClockTime next_ts;

  /* make sure timestamps increment after resetting the decoder */
  next_ts = enc->next_ts + enc->timestamp_offset;

  theora_enc_reset (enc);
  enc->granulepos_offset =
      gst_util_uint64_scale (next_ts, enc->fps_n, GST_SECOND * enc->fps_d);
  enc->timestamp_offset = next_ts;
  enc->next_ts = 0;
}

static gboolean
theora_enc_sink_event (GstPad * pad, GstEvent * event)
{
  GstTheoraEnc *enc;
  ogg_packet op;
  gboolean res;

  enc = GST_THEORA_ENC (GST_PAD_PARENT (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_NEWSEGMENT:
    {
      gboolean update;
      gdouble rate, applied_rate;
      GstFormat format;
      gint64 start, stop, time;

      gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
          &format, &start, &stop, &time);

      gst_segment_set_newsegment_full (&enc->segment, update, rate,
          applied_rate, format, start, stop, time);

      res = gst_pad_push_event (enc->srcpad, event);
      break;
    }
    case GST_EVENT_EOS:
      if (enc->initialised) {
        /* push last packet with eos flag, should not be called */
        while (th_encode_packetout (enc->encoder, 1, &op)) {
          GstClockTime next_time =
              th_granule_time (enc->encoder, op.granulepos) * GST_SECOND;

          theora_push_packet (enc, &op, GST_CLOCK_TIME_NONE, enc->next_ts,
              next_time - enc->next_ts);
          enc->next_ts = next_time;
        }
      }
      if (enc->initialised && enc->multipass_cache_fd
          && enc->multipass_mode == MULTIPASS_MODE_FIRST_PASS)
        theora_enc_write_multipass_cache (enc, TRUE, TRUE);

      theora_enc_clear_multipass_cache (enc);

      res = gst_pad_push_event (enc->srcpad, event);
      break;
    case GST_EVENT_FLUSH_STOP:
      gst_segment_init (&enc->segment, GST_FORMAT_UNDEFINED);
      res = gst_pad_push_event (enc->srcpad, event);
      break;
    case GST_EVENT_CUSTOM_DOWNSTREAM:
    {
      const GstStructure *s;

      s = gst_event_get_structure (event);

      if (gst_structure_has_name (s, "GstForceKeyUnit"))
        theora_enc_force_keyframe (enc);
      res = gst_pad_push_event (enc->srcpad, event);
      break;
    }
    default:
      res = gst_pad_push_event (enc->srcpad, event);
      break;
  }
  return res;
}

static gboolean
theora_enc_src_event (GstPad * pad, GstEvent * event)
{
  GstTheoraEnc *enc;
  gboolean res = TRUE;

  enc = GST_THEORA_ENC (GST_PAD_PARENT (pad));

  switch (GST_EVENT_TYPE (event)) {
    case GST_EVENT_CUSTOM_UPSTREAM:
    {
      const GstStructure *s;

      s = gst_event_get_structure (event);

      if (gst_structure_has_name (s, "GstForceKeyUnit")) {
        GST_OBJECT_LOCK (enc);
        enc->force_keyframe = TRUE;
        GST_OBJECT_UNLOCK (enc);
        /* consume the event */
        res = TRUE;
        gst_event_unref (event);
      } else {
        res = gst_pad_push_event (enc->sinkpad, event);
      }
      break;
    }
    default:
      res = gst_pad_push_event (enc->sinkpad, event);
      break;
  }

  return res;
}

static gboolean
theora_enc_is_discontinuous (GstTheoraEnc * enc, GstClockTime timestamp,
    GstClockTime duration)
{
  GstClockTimeDiff max_diff;
  gboolean ret = FALSE;

  /* Allow 3/4 a frame off */
  max_diff = (enc->info.fps_denominator * GST_SECOND * 3) /
      (enc->info.fps_numerator * 4);

  if (timestamp != GST_CLOCK_TIME_NONE
      && enc->expected_ts != GST_CLOCK_TIME_NONE) {
    if ((GstClockTimeDiff) (timestamp - enc->expected_ts) > max_diff) {
      GST_DEBUG_OBJECT (enc, "Incoming TS %" GST_TIME_FORMAT
          " exceeds expected value %" GST_TIME_FORMAT
          " by too much, marking discontinuity",
          GST_TIME_ARGS (timestamp), GST_TIME_ARGS (enc->expected_ts));
      ret = TRUE;
    }
  }

  if (GST_CLOCK_TIME_IS_VALID (duration))
    enc->expected_ts = timestamp + duration;
  else
    enc->expected_ts = GST_CLOCK_TIME_NONE;

  return ret;
}

static void
theora_enc_init_buffer (th_ycbcr_buffer buf, th_info * info, guint8 * data)
{
  GstVideoFormat format;
  guint i;

  switch (info->pixel_fmt) {
    case TH_PF_444:
      format = GST_VIDEO_FORMAT_Y444;
      break;
    case TH_PF_420:
      format = GST_VIDEO_FORMAT_I420;
      break;
    case TH_PF_422:
      format = GST_VIDEO_FORMAT_Y42B;
      break;
    default:
      g_assert_not_reached ();
  }

  /* According to Theora developer Timothy Terriberry, the Theora 
   * encoder will not use memory outside of pic_width/height, even when
   * the frame size is bigger. The values outside this region will be encoded
   * to default values.
   * Due to this, setting the frame's width/height as the buffer width/height
   * is perfectly ok, even though it does not strictly look ok.
   */
  for (i = 0; i < 3; i++) {
    buf[i].width =
        gst_video_format_get_component_width (format, i, info->frame_width);
    buf[i].height =
        gst_video_format_get_component_height (format, i, info->frame_height);

    buf[i].data =
        data + gst_video_format_get_component_offset (format, i,
        info->pic_width, info->pic_height);
    buf[i].stride =
        gst_video_format_get_row_stride (format, i, info->pic_width);
  }
}

static gboolean
theora_enc_read_multipass_cache (GstTheoraEnc * enc)
{
  GstBuffer *cache_buf;
  const guint8 *cache_data;
  gsize bytes_read = 0, bytes_consumed = 0;
  GIOStatus stat = G_IO_STATUS_NORMAL;
  gboolean done = FALSE;

  while (!done) {
    if (gst_adapter_available (enc->multipass_cache_adapter) == 0) {
      guint8 *data;
      gsize size;

      cache_buf = gst_buffer_new_and_alloc (512);

      data = gst_buffer_map (cache_buf, &size, NULL, GST_MAP_READ);
      stat = g_io_channel_read_chars (enc->multipass_cache_fd,
          (gchar *) data, size, &bytes_read, NULL);

      if (bytes_read <= 0) {
        gst_buffer_unmap (cache_buf, data, 0);
        gst_buffer_unref (cache_buf);
        break;
      } else {
        gst_buffer_unmap (cache_buf, data, bytes_read);
        gst_adapter_push (enc->multipass_cache_adapter, cache_buf);
      }
    }
    if (gst_adapter_available (enc->multipass_cache_adapter) == 0)
      break;

    bytes_read =
        MIN (gst_adapter_available (enc->multipass_cache_adapter), 512);

    cache_data = gst_adapter_map (enc->multipass_cache_adapter, bytes_read);

    bytes_consumed =
        th_encode_ctl (enc->encoder, TH_ENCCTL_2PASS_IN, (guint8 *) cache_data,
        bytes_read);
    gst_adapter_unmap (enc->multipass_cache_adapter, 0);

    done = bytes_consumed <= 0;
    if (bytes_consumed > 0)
      gst_adapter_flush (enc->multipass_cache_adapter, bytes_consumed);
  }

  if (stat == G_IO_STATUS_ERROR || (stat == G_IO_STATUS_EOF && bytes_read == 0)
      || bytes_consumed < 0) {
    GST_ELEMENT_ERROR (enc, RESOURCE, READ, (NULL),
        ("Failed to read multipass cache file"));
    return FALSE;
  }
  return TRUE;
}

static gboolean
theora_enc_write_multipass_cache (GstTheoraEnc * enc, gboolean begin,
    gboolean eos)
{
  GError *err = NULL;
  GIOStatus stat = G_IO_STATUS_NORMAL;
  gint bytes_read = 0;
  gsize bytes_written = 0;
  gchar *buf;

  if (begin)
    stat = g_io_channel_seek_position (enc->multipass_cache_fd, 0, G_SEEK_SET,
        &err);
  if (stat != G_IO_STATUS_ERROR) {
    do {
      bytes_read =
          th_encode_ctl (enc->encoder, TH_ENCCTL_2PASS_OUT, &buf, sizeof (buf));
      if (bytes_read > 0)
        g_io_channel_write_chars (enc->multipass_cache_fd, buf, bytes_read,
            &bytes_written, NULL);
    } while (bytes_read > 0 && bytes_written > 0);

  }

  if (stat == G_IO_STATUS_ERROR || bytes_read < 0 || bytes_written < 0) {
    if (begin) {
      if (eos)
        GST_ELEMENT_WARNING (enc, RESOURCE, WRITE, (NULL),
            ("Failed to seek to beginning of multipass cache file: %s",
                err->message));
      else
        GST_ELEMENT_ERROR (enc, RESOURCE, WRITE, (NULL),
            ("Failed to seek to beginning of multipass cache file: %s",
                err->message));
    } else {
      GST_ELEMENT_ERROR (enc, RESOURCE, WRITE, (NULL),
          ("Failed to write multipass cache file"));
    }
    if (err)
      g_error_free (err);

    return FALSE;
  }
  return TRUE;
}

static GstFlowReturn
theora_enc_chain (GstPad * pad, GstBuffer * buffer)
{
  GstTheoraEnc *enc;
  ogg_packet op;
  GstClockTime timestamp, duration, running_time;
  GstFlowReturn ret;
  gboolean force_keyframe;

  enc = GST_THEORA_ENC (GST_PAD_PARENT (pad));

  /* we keep track of two timelines.
   * - The timestamps from the incomming buffers, which we copy to the outgoing
   *   encoded buffers as-is. We need to do this as we simply forward the
   *   newsegment events.
   * - The running_time of the buffers, which we use to construct the granulepos
   *   in the packets.
   */
  timestamp = GST_BUFFER_TIMESTAMP (buffer);
  duration = GST_BUFFER_DURATION (buffer);

  running_time =
      gst_segment_to_running_time (&enc->segment, GST_FORMAT_TIME, timestamp);
  if ((gint64) running_time < 0) {
    GST_DEBUG_OBJECT (enc, "Dropping buffer, timestamp: %" GST_TIME_FORMAT,
        GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));
    gst_buffer_unref (buffer);
    return GST_FLOW_OK;
  }

  GST_OBJECT_LOCK (enc);
  if (enc->bitrate_changed) {
    long int bitrate = enc->video_bitrate;

    th_encode_ctl (enc->encoder, TH_ENCCTL_SET_BITRATE, &bitrate,
        sizeof (long int));
    enc->bitrate_changed = FALSE;
  }

  if (enc->quality_changed) {
    long int quality = enc->video_quality;

    th_encode_ctl (enc->encoder, TH_ENCCTL_SET_QUALITY, &quality,
        sizeof (long int));
    enc->quality_changed = FALSE;
  }

  /* see if we need to schedule a keyframe */
  force_keyframe = enc->force_keyframe;
  enc->force_keyframe = FALSE;
  GST_OBJECT_UNLOCK (enc);

  if (force_keyframe) {
    GstClockTime stream_time;
    GstStructure *s;

    stream_time = gst_segment_to_stream_time (&enc->segment,
        GST_FORMAT_TIME, timestamp);

    s = gst_structure_new ("GstForceKeyUnit",
        "timestamp", G_TYPE_UINT64, timestamp,
        "stream-time", G_TYPE_UINT64, stream_time,
        "running-time", G_TYPE_UINT64, running_time, NULL);

    theora_enc_force_keyframe (enc);

    gst_pad_push_event (enc->srcpad,
        gst_event_new_custom (GST_EVENT_CUSTOM_DOWNSTREAM, s));
  }

  /* make sure we copy the discont flag to the next outgoing buffer when it's
   * set on the incomming buffer */
  if (GST_BUFFER_IS_DISCONT (buffer)) {
    enc->next_discont = TRUE;
  }

  if (enc->packetno == 0) {
    /* no packets written yet, setup headers */
    GstCaps *caps;
    GstBuffer *buf;
    GSList *buffers = NULL;
    int result;

    enc->granulepos_offset = 0;
    enc->timestamp_offset = 0;

    GST_DEBUG_OBJECT (enc, "output headers");
    /* Theora streams begin with three headers; the initial header (with
       most of the codec setup parameters) which is mandated by the Ogg
       bitstream spec.  The second header holds any comment fields.  The
       third header holds the bitstream codebook.  We merely need to
       make the headers, then pass them to libtheora one at a time;
       libtheora handles the additional Ogg bitstream constraints */

    /* create the remaining theora headers */
    th_comment_clear (&enc->comment);
    th_comment_init (&enc->comment);

    while ((result =
            th_encode_flushheader (enc->encoder, &enc->comment, &op)) > 0) {
      ret =
          theora_buffer_from_packet (enc, &op, GST_CLOCK_TIME_NONE,
          GST_CLOCK_TIME_NONE, GST_CLOCK_TIME_NONE, &buf);
      if (ret != GST_FLOW_OK) {
        goto header_buffer_alloc;
      }
      buffers = g_slist_prepend (buffers, buf);
    }
    if (result < 0) {
      g_slist_foreach (buffers, (GFunc) gst_buffer_unref, NULL);
      g_slist_free (buffers);
      goto encoder_disabled;
    }

    buffers = g_slist_reverse (buffers);

    /* mark buffers and put on caps */
    caps = gst_pad_get_caps (enc->srcpad);
    caps = theora_set_header_on_caps (caps, buffers);
    GST_DEBUG ("here are the caps: %" GST_PTR_FORMAT, caps);
    gst_pad_set_caps (enc->srcpad, caps);

    g_slist_foreach (buffers, (GFunc) gst_buffer_set_caps, caps);

    gst_caps_unref (caps);

    /* push out the header buffers */
    while (buffers) {
      buf = buffers->data;
      buffers = g_slist_delete_link (buffers, buffers);
      if ((ret = theora_push_buffer (enc, buf)) != GST_FLOW_OK) {
        g_slist_foreach (buffers, (GFunc) gst_buffer_unref, NULL);
        g_slist_free (buffers);
        goto header_push;
      }
    }

    enc->granulepos_offset =
        gst_util_uint64_scale (running_time, enc->fps_n,
        GST_SECOND * enc->fps_d);
    enc->timestamp_offset = running_time;
    enc->next_ts = 0;
  }

  {
    th_ycbcr_buffer ycbcr;
    gint res;
    guint8 *data;
    gsize size;

    data = gst_buffer_map (buffer, &size, NULL, GST_MAP_READ);
    theora_enc_init_buffer (ycbcr, &enc->info, data);

    if (theora_enc_is_discontinuous (enc, running_time, duration)) {
      theora_enc_reset (enc);
      enc->granulepos_offset =
          gst_util_uint64_scale (running_time, enc->fps_n,
          GST_SECOND * enc->fps_d);
      enc->timestamp_offset = running_time;
      enc->next_ts = 0;
      enc->next_discont = TRUE;
    }

    if (enc->multipass_cache_fd
        && enc->multipass_mode == MULTIPASS_MODE_SECOND_PASS) {
      if (!theora_enc_read_multipass_cache (enc)) {
        gst_buffer_unmap (buffer, data, size);
        ret = GST_FLOW_ERROR;
        goto multipass_read_failed;
      }
    }

    res = th_encode_ycbcr_in (enc->encoder, ycbcr);
    /* none of the failure cases can happen here */
    g_assert (res == 0);

    if (enc->multipass_cache_fd
        && enc->multipass_mode == MULTIPASS_MODE_FIRST_PASS) {
      if (!theora_enc_write_multipass_cache (enc, FALSE, FALSE)) {
        gst_buffer_unmap (buffer, data, size);
        ret = GST_FLOW_ERROR;
        goto multipass_write_failed;
      }
    }

    ret = GST_FLOW_OK;
    while (th_encode_packetout (enc->encoder, 0, &op)) {
      GstClockTime next_time;

      next_time = th_granule_time (enc->encoder, op.granulepos) * GST_SECOND;

      ret =
          theora_push_packet (enc, &op, timestamp, enc->next_ts,
          next_time - enc->next_ts);

      enc->next_ts = next_time;
      if (ret != GST_FLOW_OK) {
        gst_buffer_unmap (buffer, data, size);
        goto data_push;
      }
    }
    gst_buffer_unmap (buffer, data, size);
    gst_buffer_unref (buffer);
  }

  return ret;

  /* ERRORS */
multipass_read_failed:
  {
    gst_buffer_unref (buffer);
    return ret;
  }
multipass_write_failed:
  {
    gst_buffer_unref (buffer);
    return ret;
  }
header_buffer_alloc:
  {
    gst_buffer_unref (buffer);
    return ret;
  }
header_push:
  {
    gst_buffer_unref (buffer);
    return ret;
  }
data_push:
  {
    gst_buffer_unref (buffer);
    return ret;
  }
encoder_disabled:
  {
    GST_ELEMENT_ERROR (enc, STREAM, ENCODE, (NULL),
        ("libtheora has been compiled with the encoder disabled"));
    gst_buffer_unref (buffer);
    return GST_FLOW_ERROR;
  }
}

static GstStateChangeReturn
theora_enc_change_state (GstElement * element, GstStateChange transition)
{
  GstTheoraEnc *enc;
  GstStateChangeReturn ret;

  enc = GST_THEORA_ENC (element);

  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
      break;
    case GST_STATE_CHANGE_READY_TO_PAUSED:
      GST_DEBUG_OBJECT (enc, "READY->PAUSED Initing theora state");
      th_info_init (&enc->info);
      th_comment_init (&enc->comment);
      enc->packetno = 0;
      enc->force_keyframe = FALSE;

      if (enc->multipass_mode >= MULTIPASS_MODE_FIRST_PASS) {
        GError *err = NULL;

        if (!enc->multipass_cache_file) {
          ret = GST_STATE_CHANGE_FAILURE;
          GST_ELEMENT_ERROR (enc, LIBRARY, SETTINGS, (NULL), (NULL));
          return ret;
        }
        enc->multipass_cache_fd =
            g_io_channel_new_file (enc->multipass_cache_file,
            (enc->multipass_mode == MULTIPASS_MODE_FIRST_PASS ? "w" : "r"),
            &err);

        if (enc->multipass_mode == MULTIPASS_MODE_SECOND_PASS)
          enc->multipass_cache_adapter = gst_adapter_new ();

        if (!enc->multipass_cache_fd) {
          ret = GST_STATE_CHANGE_FAILURE;
          GST_ELEMENT_ERROR (enc, RESOURCE, OPEN_READ, (NULL),
              ("Failed to open multipass cache file: %s", err->message));
          g_error_free (err);
          return ret;
        }

        g_io_channel_set_encoding (enc->multipass_cache_fd, NULL, NULL);
      }
      break;
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
      break;
    default:
      break;
  }

  ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

  switch (transition) {
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
      break;
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      GST_DEBUG_OBJECT (enc, "PAUSED->READY Clearing theora state");
      if (enc->encoder) {
        th_encode_free (enc->encoder);
        enc->encoder = NULL;
      }
      th_comment_clear (&enc->comment);
      th_info_clear (&enc->info);

      theora_enc_clear (enc);
      enc->initialised = FALSE;
      break;
    case GST_STATE_CHANGE_READY_TO_NULL:
      break;
    default:
      break;
  }

  return ret;
}

static void
theora_enc_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstTheoraEnc *enc = GST_THEORA_ENC (object);

  switch (prop_id) {
    case PROP_CENTER:
    case PROP_BORDER:
    case PROP_QUICK:
    case PROP_KEYFRAME_THRESHOLD:
    case PROP_KEYFRAME_MINDISTANCE:
    case PROP_NOISE_SENSITIVITY:
    case PROP_SHARPNESS:
      /* kept for API compat, but ignored */
      break;
    case PROP_BITRATE:
      GST_OBJECT_LOCK (enc);
      enc->video_bitrate = g_value_get_int (value) * 1000;
      enc->bitrate_changed = TRUE;
      GST_OBJECT_UNLOCK (enc);
      break;
    case PROP_QUALITY:
      GST_OBJECT_LOCK (enc);
      if (GST_STATE (enc) >= GST_STATE_PAUSED && enc->video_bitrate > 0) {
        GST_WARNING_OBJECT (object, "Can't change from bitrate to quality mode"
            " while playing");
      } else {
        enc->video_quality = g_value_get_int (value);
        enc->video_bitrate = 0;
        enc->quality_changed = TRUE;
      }
      GST_OBJECT_UNLOCK (enc);
      break;
    case PROP_KEYFRAME_AUTO:
      enc->keyframe_auto = g_value_get_boolean (value);
      break;
    case PROP_KEYFRAME_FREQ:
      enc->keyframe_freq = g_value_get_int (value);
      break;
    case PROP_KEYFRAME_FREQ_FORCE:
      enc->keyframe_force = g_value_get_int (value);
      break;
    case PROP_SPEEDLEVEL:
      enc->speed_level = g_value_get_int (value);
      if (enc->encoder) {
        th_encode_ctl (enc->encoder, TH_ENCCTL_SET_SPLEVEL, &enc->speed_level,
            sizeof (enc->speed_level));
      }
      break;
    case PROP_VP3_COMPATIBLE:
      enc->vp3_compatible = g_value_get_boolean (value);
      break;
    case PROP_DROP_FRAMES:
      enc->drop_frames = g_value_get_boolean (value);
      break;
    case PROP_CAP_OVERFLOW:
      enc->cap_overflow = g_value_get_boolean (value);
      break;
    case PROP_CAP_UNDERFLOW:
      enc->cap_underflow = g_value_get_boolean (value);
      break;
    case PROP_RATE_BUFFER:
      enc->rate_buffer = g_value_get_int (value);
      break;
    case PROP_MULTIPASS_CACHE_FILE:
      enc->multipass_cache_file = g_value_dup_string (value);
      break;
    case PROP_MULTIPASS_MODE:
      enc->multipass_mode = g_value_get_enum (value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
theora_enc_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstTheoraEnc *enc = GST_THEORA_ENC (object);

  switch (prop_id) {
    case PROP_CENTER:
      g_value_set_boolean (value, TRUE);
      break;
    case PROP_BORDER:
      g_value_set_enum (value, BORDER_BLACK);
      break;
    case PROP_BITRATE:
      GST_OBJECT_LOCK (enc);
      g_value_set_int (value, enc->video_bitrate / 1000);
      GST_OBJECT_UNLOCK (enc);
      break;
    case PROP_QUALITY:
      GST_OBJECT_LOCK (enc);
      g_value_set_int (value, enc->video_quality);
      GST_OBJECT_UNLOCK (enc);
      break;
    case PROP_QUICK:
      g_value_set_boolean (value, TRUE);
      break;
    case PROP_KEYFRAME_AUTO:
      g_value_set_boolean (value, enc->keyframe_auto);
      break;
    case PROP_KEYFRAME_FREQ:
      g_value_set_int (value, enc->keyframe_freq);
      break;
    case PROP_KEYFRAME_FREQ_FORCE:
      g_value_set_int (value, enc->keyframe_force);
      break;
    case PROP_KEYFRAME_THRESHOLD:
      g_value_set_int (value, 80);
      break;
    case PROP_KEYFRAME_MINDISTANCE:
      g_value_set_int (value, 8);
      break;
    case PROP_NOISE_SENSITIVITY:
      g_value_set_int (value, 1);
      break;
    case PROP_SHARPNESS:
      g_value_set_int (value, 0);
      break;
    case PROP_SPEEDLEVEL:
      g_value_set_int (value, enc->speed_level);
      break;
    case PROP_VP3_COMPATIBLE:
      g_value_set_boolean (value, enc->vp3_compatible);
      break;
    case PROP_DROP_FRAMES:
      g_value_set_boolean (value, enc->drop_frames);
      break;
    case PROP_CAP_OVERFLOW:
      g_value_set_boolean (value, enc->cap_overflow);
      break;
    case PROP_CAP_UNDERFLOW:
      g_value_set_boolean (value, enc->cap_underflow);
      break;
    case PROP_RATE_BUFFER:
      g_value_set_int (value, enc->rate_buffer);
      break;
    case PROP_MULTIPASS_CACHE_FILE:
      g_value_set_string (value, enc->multipass_cache_file);
      break;
    case PROP_MULTIPASS_MODE:
      g_value_set_enum (value, enc->multipass_mode);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}