gstreamer/gst/mpeg1videoparse/gstmp1videoparse.c

/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 *
 * 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.
 */

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

/*#define GST_DEBUG_ENABLED */
#include "gstmp1videoparse.h"

/* Start codes. */
#define SEQ_START_CODE 0x000001b3
#define GOP_START_CODE 0x000001b8
#define PICTURE_START_CODE 0x00000100
#define SLICE_MIN_START_CODE 0x00000101
#define SLICE_MAX_START_CODE 0x000001af
#define EXT_START_CODE 0x000001b5
#define USER_START_CODE 0x000001b2
#define SEQUENCE_ERROR_CODE 0x000001b4
#define SEQ_END_CODE 0x000001b7

/* elementfactory information */
static GstElementDetails mpeg1videoparse_details =
GST_ELEMENT_DETAILS ("MPEG 1 Video Parser",
    "Codec/Parser/Video",
    "Parses and frames MPEG 1 video streams, provides seek",
    "Wim Taymans <wim.taymans@chello.be>");

static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/mpeg, "
        "mpegversion = (int) 1, "
        "systemstream = (boolean) false, "
        "width = (int) [ 16, 4096 ], "
        "height = (int) [ 16, 4096 ], "
        "pixel_width = (int) [ 1, 255 ], "
        "pixel_height = (int) [ 1, 255 ], " "framerate = (double) [ 0, MAX ]")
    );

static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS ("video/mpeg, "
        "mpegversion = (int) 1, " "systemstream = (boolean) false")
    );

/* Mp1VideoParse signals and args */
enum
{
  /* FILL ME */
  LAST_SIGNAL
};

enum
{
  ARG_0
      /* FILL ME */
};

static void gst_mp1videoparse_class_init (Mp1VideoParseClass * klass);
static void gst_mp1videoparse_base_init (Mp1VideoParseClass * klass);
static void gst_mp1videoparse_init (Mp1VideoParse * mp1videoparse);

static void gst_mp1videoparse_chain (GstPad * pad, GstData * _data);
static void gst_mp1videoparse_real_chain (Mp1VideoParse * mp1videoparse,
    GstBuffer * buf, GstPad * outpad);
static void gst_mp1videoparse_flush (Mp1VideoParse * mp1videoparse);
static GstStateChangeReturn
gst_mp1videoparse_change_state (GstElement * element,
    GstStateChange transition);

static GstElementClass *parent_class = NULL;

/*static guint gst_mp1videoparse_signals[LAST_SIGNAL] = { 0 }; */

GType
mp1videoparse_get_type (void)
{
  static GType mp1videoparse_type = 0;

  if (!mp1videoparse_type) {
    static const GTypeInfo mp1videoparse_info = {
      sizeof (Mp1VideoParseClass),
      (GBaseInitFunc) gst_mp1videoparse_base_init,
      NULL,
      (GClassInitFunc) gst_mp1videoparse_class_init,
      NULL,
      NULL,
      sizeof (Mp1VideoParse),
      0,
      (GInstanceInitFunc) gst_mp1videoparse_init,
    };

    mp1videoparse_type =
        g_type_register_static (GST_TYPE_ELEMENT, "Mp1VideoParse",
        &mp1videoparse_info, 0);
  }
  return mp1videoparse_type;
}

static void
gst_mp1videoparse_base_init (Mp1VideoParseClass * klass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&src_factory));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&sink_factory));
  gst_element_class_set_details (element_class, &mpeg1videoparse_details);
}

static void
gst_mp1videoparse_class_init (Mp1VideoParseClass * klass)
{
  GstElementClass *gstelement_class;

  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

  gstelement_class->change_state = gst_mp1videoparse_change_state;
}

static void
gst_mp1videoparse_init (Mp1VideoParse * mp1videoparse)
{
  mp1videoparse->sinkpad =
      gst_pad_new_from_template (gst_static_pad_template_get (&sink_factory),
      "sink");
  gst_element_add_pad (GST_ELEMENT (mp1videoparse), mp1videoparse->sinkpad);
  gst_pad_set_chain_function (mp1videoparse->sinkpad, gst_mp1videoparse_chain);

  mp1videoparse->srcpad =
      gst_pad_new_from_template (gst_static_pad_template_get (&src_factory),
      "src");
  gst_element_add_pad (GST_ELEMENT (mp1videoparse), mp1videoparse->srcpad);
  gst_pad_use_explicit_caps (mp1videoparse->srcpad);

  mp1videoparse->partialbuf = NULL;
  mp1videoparse->need_resync = FALSE;
  mp1videoparse->need_discont = TRUE;
  mp1videoparse->last_pts = GST_CLOCK_TIME_NONE;
  mp1videoparse->picture_in_buffer = 0;
  mp1videoparse->width = mp1videoparse->height = -1;
  mp1videoparse->fps = mp1videoparse->asr = 0.;
}

static void
mp1videoparse_parse_seq (Mp1VideoParse * mp1videoparse, GstBuffer * buf)
{
  gint width, height, asr_idx, fps_idx;
  gfloat asr_table[] = { 0., 1.,
    0.6735, 0.7031, 0.7615, 0.8055, 0.8437,
    0.8935, 0.9157, 0.9815, 1.0255, 1.0695,
    1.0950, 1.1575, 1.2015
  };
  gfloat fps_table[] = { 0., 24. / 1.001, 24., 25.,
    30. / 1.001, 30.,
    50., 60. / 1.001, 60.
  };
  guint32 n = GST_READ_UINT32_BE (GST_BUFFER_DATA (buf));

  width = (n & 0xfff00000) >> 20;
  height = (n & 0x000fff00) >> 8;
  asr_idx = (n & 0x000000f0) >> 4;
  fps_idx = (n & 0x0000000f) >> 0;

  if (fps_idx >= 9 || fps_idx <= 0)
    fps_idx = 3;                /* well, we need a default */
  if (asr_idx >= 15 || asr_idx <= 0)
    asr_idx = 1;                /* no aspect ratio */

  if (asr_table[asr_idx] != mp1videoparse->asr ||
      fps_table[fps_idx] != mp1videoparse->fps ||
      width != mp1videoparse->width || height != mp1videoparse->height) {
    GstCaps *caps;
    gint p_w, p_h;

    mp1videoparse->asr = asr_table[asr_idx];
    mp1videoparse->fps = fps_table[fps_idx];
    mp1videoparse->width = width;
    mp1videoparse->height = height;

    p_w = (asr_table[asr_idx] < 1.0) ? (100 / asr_table[asr_idx]) : 1;
    p_h = (asr_table[asr_idx] > 1.0) ? (100 * asr_table[asr_idx]) : 1;

    caps = gst_caps_new_simple ("video/mpeg",
        "systemstream", G_TYPE_BOOLEAN, FALSE,
        "mpegversion", G_TYPE_INT, 1,
        "width", G_TYPE_INT, width,
        "height", G_TYPE_INT, height,
        "framerate", G_TYPE_DOUBLE, fps_table[fps_idx],
        "pixel_width", G_TYPE_INT, p_w, "pixel_height", G_TYPE_INT, p_h, NULL);

    GST_DEBUG ("New mpeg1videoparse caps: " GST_PTR_FORMAT, caps);

    gst_pad_set_explicit_caps (mp1videoparse->srcpad, caps);
  }
}

static gboolean
mp1videoparse_valid_sync (Mp1VideoParse * mp1videoparse, guint32 head,
    GstBuffer * buf)
{
  switch (head) {
    case SEQ_START_CODE:{
      GstBuffer *subbuf = gst_buffer_create_sub (buf, 4,
          GST_BUFFER_SIZE (buf) - 4);

      mp1videoparse_parse_seq (mp1videoparse, subbuf);
      gst_buffer_unref (subbuf);
      return TRUE;
    }
    case GOP_START_CODE:
    case PICTURE_START_CODE:
    case USER_START_CODE:
    case EXT_START_CODE:
      return TRUE;
    default:
      if (head >= SLICE_MIN_START_CODE && head <= SLICE_MAX_START_CODE)
        return TRUE;
  }

  return FALSE;
}

static gint
mp1videoparse_find_next_gop (Mp1VideoParse * mp1videoparse, GstBuffer * buf)
{
  guchar *data = GST_BUFFER_DATA (buf);
  gulong size = GST_BUFFER_SIZE (buf);
  gulong offset = 0;
  gint sync_zeros = 0;
  gboolean have_sync = FALSE;

  while (offset < size) {
    guchar byte = *(data + offset);

    offset++;
    if (byte == 0) {
      sync_zeros++;
    } else if (byte == 1 && sync_zeros >= 2) {
      sync_zeros = 0;
      have_sync = TRUE;
    } else if (have_sync) {
      if (byte == (SEQ_START_CODE & 0xff) || byte == (GOP_START_CODE & 0xff)) {
        return offset - 4;
      } else {
        sync_zeros = 0;
        have_sync = FALSE;
      }
    } else {
      sync_zeros = 0;
    }
  }

  return -1;
}

static guint64
gst_mp1videoparse_time_code (guchar * gop, gfloat fps)
{
  guint32 data = GST_READ_UINT32_BE (gop);

  return ((((data & 0xfc000000) >> 26) * 3600 * GST_SECOND) +   /* hours */
      (((data & 0x03f00000) >> 20) * 60 * GST_SECOND) + /* minutes */
      (((data & 0x0007e000) >> 13) * GST_SECOND) +      /* seconds */
      (((data & 0x00001f80) >> 7) * GST_SECOND / fps)); /* frames */
}

static void
gst_mp1videoparse_flush (Mp1VideoParse * mp1videoparse)
{
  GST_DEBUG ("mp1videoparse: flushing");
  if (mp1videoparse->partialbuf) {
    gst_buffer_unref (mp1videoparse->partialbuf);
    mp1videoparse->partialbuf = NULL;
  }
  mp1videoparse->need_resync = TRUE;
  mp1videoparse->in_flush = TRUE;
  mp1videoparse->picture_in_buffer = 0;
}

static void
gst_mp1videoparse_chain (GstPad * pad, GstData * _data)
{
  GstBuffer *buf = GST_BUFFER (_data);
  Mp1VideoParse *mp1videoparse;

  g_return_if_fail (pad != NULL);
  g_return_if_fail (GST_IS_PAD (pad));
  g_return_if_fail (buf != NULL);

  mp1videoparse = GST_MP1VIDEOPARSE (GST_OBJECT_PARENT (pad));

  gst_mp1videoparse_real_chain (mp1videoparse, buf, mp1videoparse->srcpad);
}

static void
gst_mp1videoparse_real_chain (Mp1VideoParse * mp1videoparse, GstBuffer * buf,
    GstPad * outpad)
{
  guchar *data;
  gulong size, offset = 0;
  GstBuffer *outbuf;
  gint sync_state;
  gboolean have_sync;
  guchar sync_byte;
  guint32 head;
  gint sync_pos;
  guint64 time_stamp;
  GstBuffer *temp;

  time_stamp = GST_BUFFER_TIMESTAMP (buf);

  if (GST_IS_EVENT (buf)) {
    GstEvent *event = GST_EVENT (buf);

    switch (GST_EVENT_TYPE (event)) {
      case GST_EVENT_DISCONTINUOUS:
        mp1videoparse->need_discont = TRUE;
        /* fall-through */
      case GST_EVENT_FLUSH:
        gst_mp1videoparse_flush (mp1videoparse);
        break;
      case GST_EVENT_EOS:
        gst_mp1videoparse_flush (mp1videoparse);
        gst_event_ref (event);
        gst_pad_push (outpad, GST_DATA (event));
        gst_element_set_eos (GST_ELEMENT (mp1videoparse));
        break;
      default:
        GST_DEBUG ("Unhandled event type %d", GST_EVENT_TYPE (event));
        break;
    }

    gst_event_unref (event);
    return;
  }


  if (mp1videoparse->partialbuf) {
    GstBuffer *merge;

    offset = GST_BUFFER_SIZE (mp1videoparse->partialbuf);
    merge = gst_buffer_merge (mp1videoparse->partialbuf, buf);

    gst_buffer_unref (mp1videoparse->partialbuf);
    gst_buffer_unref (buf);

    mp1videoparse->partialbuf = merge;
  } else {
    mp1videoparse->partialbuf = buf;
    offset = 0;
  }

  data = GST_BUFFER_DATA (mp1videoparse->partialbuf);
  size = GST_BUFFER_SIZE (mp1videoparse->partialbuf);

  GST_DEBUG ("mp1videoparse: received buffer of %ld bytes %" G_GINT64_FORMAT,
      size, GST_BUFFER_TIMESTAMP (buf));

  do {
    data = GST_BUFFER_DATA (mp1videoparse->partialbuf);
    size = GST_BUFFER_SIZE (mp1videoparse->partialbuf);

    head = GST_READ_UINT32_BE (data);

    GST_DEBUG ("mp1videoparse: head is %08x", (unsigned int) head);

    if (!mp1videoparse_valid_sync (mp1videoparse, head,
            mp1videoparse->partialbuf) || mp1videoparse->need_resync) {
      sync_pos =
          mp1videoparse_find_next_gop (mp1videoparse,
          mp1videoparse->partialbuf);
      if (sync_pos >= 0) {
        mp1videoparse->need_resync = FALSE;
        GST_DEBUG ("mp1videoparse: found new gop at %d", sync_pos);

        if (sync_pos != 0) {
          temp =
              gst_buffer_create_sub (mp1videoparse->partialbuf, sync_pos,
              size - sync_pos);
          g_assert (temp != NULL);
          gst_buffer_unref (mp1videoparse->partialbuf);
          mp1videoparse->partialbuf = temp;
          data = GST_BUFFER_DATA (mp1videoparse->partialbuf);
          size = GST_BUFFER_SIZE (mp1videoparse->partialbuf);
          offset = 0;
        }

        head = GST_READ_UINT32_BE (data);
        /* re-call this function so that if we hadn't already, we can
         * now read the sequence header and parse video properties,
         * set caps, stream data, be happy, bla, bla, bla... */
        if (!mp1videoparse_valid_sync (mp1videoparse, head,
                mp1videoparse->partialbuf))
          g_error ("Found sync but no valid sync point at pos 0x0");
      } else {
        GST_DEBUG ("mp1videoparse: could not sync");
        gst_buffer_unref (mp1videoparse->partialbuf);
        mp1videoparse->partialbuf = NULL;
        return;
      }
    }

    if (mp1videoparse->picture_in_buffer == 1 &&
        time_stamp != GST_CLOCK_TIME_NONE) {
      mp1videoparse->last_pts = time_stamp;
    }

    sync_state = 0;
    have_sync = FALSE;

    GST_DEBUG ("mp1videoparse: searching sync");

    while (offset < size - 1) {
      sync_byte = *(data + offset);
      if (sync_byte == 0) {
        sync_state++;
      } else if ((sync_byte == 1) && (sync_state >= 2)) {
        GST_DEBUG ("mp1videoparse: code 0x000001%02x", data[offset + 1]);
        if (data[offset + 1] == (PICTURE_START_CODE & 0xff)) {
          mp1videoparse->picture_in_buffer++;
          if (mp1videoparse->picture_in_buffer == 1) {
            if (time_stamp != GST_CLOCK_TIME_NONE) {
              mp1videoparse->last_pts = time_stamp;
            }
            sync_state = 0;
          } else if (mp1videoparse->picture_in_buffer == 2) {
            have_sync = TRUE;
            break;
          } else {
            GST_DEBUG ("mp1videoparse: %d in buffer",
                mp1videoparse->picture_in_buffer);
            g_assert_not_reached ();
          }
        }
        /* A new sequence (or GOP) is a valid sync too. Note that the
         * sequence header should be put in the next buffer, not here. */
        else if (data[offset + 1] == (SEQ_START_CODE & 0xFF) ||
            data[offset + 1] == (GOP_START_CODE & 0xFF)) {
          if (mp1videoparse->picture_in_buffer == 0 &&
              data[offset + 1] == (GOP_START_CODE & 0xFF)) {
            mp1videoparse->last_pts = gst_mp1videoparse_time_code (&data[2],
                mp1videoparse->fps);
          } else if (mp1videoparse->picture_in_buffer == 1) {
            have_sync = TRUE;
            break;
          } else {
            g_assert (mp1videoparse->picture_in_buffer == 0);
          }
        }
        /* end-of-sequence is a valid sync point and should be included
         * in the current picture, not the next. */
        else if (data[offset + 1] == (SEQ_END_CODE & 0xFF)) {
          if (mp1videoparse->picture_in_buffer == 1) {
            offset += 4;
            have_sync = TRUE;
            break;
          } else {
            g_assert (mp1videoparse->picture_in_buffer == 0);
          }
        } else
          sync_state = 0;
      }
      /* something else... */
      else
        sync_state = 0;

      /* go down the buffer */
      offset++;
    }

    if (have_sync) {
      offset -= 2;
      GST_DEBUG ("mp1videoparse: synced");

      outbuf = gst_buffer_create_sub (mp1videoparse->partialbuf, 0, offset);
      g_assert (outbuf != NULL);
      GST_BUFFER_TIMESTAMP (outbuf) = mp1videoparse->last_pts;
      GST_BUFFER_DURATION (outbuf) = GST_SECOND / mp1videoparse->fps;
      mp1videoparse->last_pts += GST_BUFFER_DURATION (outbuf);

      if (mp1videoparse->in_flush) {
        /* FIXME, send a flush event here */
        mp1videoparse->in_flush = FALSE;
      }

      if (GST_PAD_CAPS (outpad) != NULL) {
        if (mp1videoparse->need_discont &&
            GST_BUFFER_TIMESTAMP_IS_VALID (outbuf)) {
          GstEvent *event = gst_event_new_discontinuous (FALSE,
              GST_FORMAT_TIME, GST_BUFFER_TIMESTAMP (outbuf),
              GST_FORMAT_UNDEFINED);

          GST_DEBUG ("prepending discont event");
          gst_pad_push (outpad, GST_DATA (event));
          mp1videoparse->need_discont = FALSE;
        }
        GST_DEBUG ("mp1videoparse: pushing  %d bytes %" G_GUINT64_FORMAT,
            GST_BUFFER_SIZE (outbuf), GST_BUFFER_TIMESTAMP (outbuf));
        gst_pad_push (outpad, GST_DATA (outbuf));
        GST_DEBUG ("mp1videoparse: pushing  done");
      } else {
        GST_DEBUG ("No capsnego yet, delaying buffer push");
        gst_buffer_unref (outbuf);
      }
      mp1videoparse->picture_in_buffer = 0;

      if (size != offset) {
        temp =
            gst_buffer_create_sub (mp1videoparse->partialbuf, offset,
            size - offset);
      } else {
        temp = NULL;
      }
      gst_buffer_unref (mp1videoparse->partialbuf);
      mp1videoparse->partialbuf = temp;
      offset = 0;
    } else {
      if (time_stamp != GST_CLOCK_TIME_NONE)
        mp1videoparse->last_pts = time_stamp;
      return;
    }
  } while (mp1videoparse->partialbuf != NULL);
}

static GstStateChangeReturn
gst_mp1videoparse_change_state (GstElement * element, GstStateChange transition)
{
  Mp1VideoParse *mp1videoparse;

  g_return_val_if_fail (GST_IS_MP1VIDEOPARSE (element),
      GST_STATE_CHANGE_FAILURE);

  mp1videoparse = GST_MP1VIDEOPARSE (element);

  switch (transition) {
    case GST_STATE_CHANGE_PAUSED_TO_READY:
      gst_mp1videoparse_flush (mp1videoparse);
      mp1videoparse->need_discont = TRUE;
      mp1videoparse->width = mp1videoparse->height = -1;
      mp1videoparse->fps = mp1videoparse->asr = 0.;
      break;
    default:
      break;
  }

  if (GST_ELEMENT_CLASS (parent_class)->change_state)
    return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);

  return GST_STATE_CHANGE_SUCCESS;
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "mpeg1videoparse",
      GST_RANK_NONE, GST_TYPE_MP1VIDEOPARSE);
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "mpeg1videoparse",
    "MPEG-1 video parser",
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)