gstreamer/ext/ffmpeg/gstffmpegenc.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

#include <assert.h>
#include <string.h>

#ifdef HAVE_FFMPEG_UNINSTALLED
#include <avcodec.h>
#else
#include <ffmpeg/avcodec.h>
#endif

#include <gst/gst.h>

#include "gstffmpegcodecmap.h"

typedef struct _GstFFMpegEnc GstFFMpegEnc;

struct _GstFFMpegEnc {
  GstElement element;

  /* We need to keep track of our pads, so we do so here. */
  GstPad *srcpad;
  GstPad *sinkpad;

  AVCodecContext *context;
  AVFrame *picture;
  gboolean opened;
  GstBuffer *cache;

  /* cache */
  gulong bitrate;
  gint me_method;
  gint gop_size;
  gulong buffer_size;
};

typedef struct _GstFFMpegEncClass GstFFMpegEncClass;

struct _GstFFMpegEncClass {
  GstElementClass parent_class;

  AVCodec *in_plugin;
  GstPadTemplate *srctempl, *sinktempl;
};

typedef struct {
  AVCodec *in_plugin;
  GstCaps *srccaps, *sinkcaps;
} GstFFMpegEncClassParams;

#define GST_TYPE_FFMPEGENC \
  (gst_ffmpegenc_get_type())
#define GST_FFMPEGENC(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_FFMPEGENC,GstFFMpegEnc))
#define GST_FFMPEGENC_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_FFMPEGENC,GstFFMpegEncClass))
#define GST_IS_FFMPEGENC(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_FFMPEGENC))
#define GST_IS_FFMPEGENC_CLASS(obj) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_FFMPEGENC))

#define VIDEO_BUFFER_SIZE (1024*1024)

enum {
  /* FILL ME */
  LAST_SIGNAL
};

enum {
  ARG_0,
  ARG_BIT_RATE,
  ARG_GOP_SIZE,
  ARG_ME_METHOD,
  ARG_BUFSIZE
  /* FILL ME */
};

#define GST_TYPE_ME_METHOD (gst_ffmpegenc_me_method_get_type())
static GType
gst_ffmpegenc_me_method_get_type (void)
{
  static GType ffmpegenc_me_method_type = 0;
  static GEnumValue ffmpegenc_me_methods[] = {
    { ME_ZERO,  "0", "zero" },
    { ME_FULL,  "1", "full" },
    { ME_LOG,   "2", "logarithmic" },
    { ME_PHODS, "3", "phods" },
    { ME_EPZS,  "4", "epzs" },
    { ME_X1   , "5", "x1" },
    { 0, NULL, NULL },
  };
  if (!ffmpegenc_me_method_type) {
    ffmpegenc_me_method_type = g_enum_register_static ("GstFFMpegEncMeMethod", ffmpegenc_me_methods);
  }
  return ffmpegenc_me_method_type;
}

static GHashTable *enc_global_plugins;

/* A number of functon prototypes are given so we can refer to them later. */
static void	gst_ffmpegenc_class_init	(GstFFMpegEncClass *klass);
static void	gst_ffmpegenc_base_init		(GstFFMpegEncClass *klass);
static void	gst_ffmpegenc_init		(GstFFMpegEnc *ffmpegenc);
static void	gst_ffmpegenc_dispose		(GObject *object);

static GstPadLinkReturn
		gst_ffmpegenc_connect		(GstPad *pad, const GstCaps *caps);
static void	gst_ffmpegenc_chain_video	(GstPad *pad, GstData *_data);
static void	gst_ffmpegenc_chain_audio	(GstPad *pad, GstData *_data);

static void	gst_ffmpegenc_set_property	(GObject *object,
						 guint prop_id,
						 const GValue *value,
						 GParamSpec *pspec);
static void	gst_ffmpegenc_get_property	(GObject *object,
						 guint prop_id,
						 GValue *value,
						 GParamSpec *pspec);

static GstElementStateReturn
		gst_ffmpegenc_change_state	(GstElement *element);

static GstElementClass *parent_class = NULL;

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

static void
gst_ffmpegenc_base_init (GstFFMpegEncClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
  GstFFMpegEncClassParams *params;
  GstElementDetails details;
  GstPadTemplate *srctempl, *sinktempl;

  params = g_hash_table_lookup (enc_global_plugins,
		  GINT_TO_POINTER (G_OBJECT_CLASS_TYPE (gobject_class)));
  /* HACK: if we don't have a GType yet, our params are stored at position 0 */
  if (!params) {
    params = g_hash_table_lookup (enc_global_plugins,
		  GINT_TO_POINTER (0));
  }
  g_assert (params);

  /* construct the element details struct */
  details.longname = g_strdup_printf("FFMPEG %s encoder",
				      params->in_plugin->name);
  details.klass = g_strdup_printf("Codec/Encoder/%s",
				   (params->in_plugin->type == CODEC_TYPE_VIDEO) ?
				   "Video" : "Audio");
  details.description = g_strdup_printf("FFMPEG %s encoder",
					 params->in_plugin->name);
  details.author = "Wim Taymans <wim.taymans@chello.be>, "
		   "Ronald Bultje <rbultje@ronald.bitfreak.net>";
  gst_element_class_set_details (element_class, &details);
  g_free (details.longname);
  g_free (details.klass);
  g_free (details.description);

  /* pad templates */
  sinktempl = gst_pad_template_new ("sink", GST_PAD_SINK,
				    GST_PAD_ALWAYS, params->sinkcaps);
  srctempl = gst_pad_template_new ("src", GST_PAD_SRC,
				   GST_PAD_ALWAYS, params->srccaps);

  gst_element_class_add_pad_template (element_class, srctempl);
  gst_element_class_add_pad_template (element_class, sinktempl);

  klass->in_plugin = params->in_plugin;
  klass->srctempl = srctempl;
  klass->sinktempl = sinktempl;
}

static void
gst_ffmpegenc_class_init (GstFFMpegEncClass *klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass*)klass;
  gstelement_class = (GstElementClass*)klass;

  parent_class = g_type_class_ref(GST_TYPE_ELEMENT);

  if (klass->in_plugin->type == CODEC_TYPE_VIDEO) {
    g_object_class_install_property(G_OBJECT_CLASS (klass), ARG_BIT_RATE,
      g_param_spec_ulong ("bitrate","Bit Rate",
			  "Target Video Bitrate",
			  0, G_MAXULONG, 300000, G_PARAM_READWRITE)); 
    g_object_class_install_property(G_OBJECT_CLASS (klass), ARG_GOP_SIZE,
      g_param_spec_int ("gop_size","GOP Size",
			"Number of frames within one GOP",
			0, G_MAXINT, 15, G_PARAM_READWRITE)); 
    g_object_class_install_property(G_OBJECT_CLASS (klass), ARG_ME_METHOD,
      g_param_spec_enum ("me_method","ME Method",
			 "Motion Estimation Method",
                         GST_TYPE_ME_METHOD, ME_LOG, G_PARAM_READWRITE));
    g_object_class_install_property(G_OBJECT_CLASS(klass), ARG_BUFSIZE,
      g_param_spec_ulong("buffer_size", "Buffer Size",
                         "Size of the video buffers",
                         0,G_MAXULONG,0,G_PARAM_READWRITE));
  }
  else if (klass->in_plugin->type == CODEC_TYPE_AUDIO) {
    g_object_class_install_property(G_OBJECT_CLASS (klass), ARG_BIT_RATE,
      g_param_spec_ulong ("bitrate","Bit Rate",
			  "Target Audio Bitrate",
			  0, G_MAXULONG, 128000, G_PARAM_READWRITE)); 
  }

  gobject_class->set_property = gst_ffmpegenc_set_property;
  gobject_class->get_property = gst_ffmpegenc_get_property;

  gstelement_class->change_state = gst_ffmpegenc_change_state;

  gobject_class->dispose = gst_ffmpegenc_dispose;
}

static void
gst_ffmpegenc_init(GstFFMpegEnc *ffmpegenc)
{
  GstFFMpegEncClass *oclass = (GstFFMpegEncClass*)(G_OBJECT_GET_CLASS (ffmpegenc));

  /* setup pads */
  ffmpegenc->sinkpad = gst_pad_new_from_template (oclass->sinktempl, "sink");
  gst_pad_set_link_function (ffmpegenc->sinkpad, gst_ffmpegenc_connect);
  ffmpegenc->srcpad = gst_pad_new_from_template (oclass->srctempl, "src");
  gst_pad_use_explicit_caps (ffmpegenc->srcpad);

  gst_element_add_pad (GST_ELEMENT (ffmpegenc), ffmpegenc->sinkpad);
  gst_element_add_pad (GST_ELEMENT (ffmpegenc), ffmpegenc->srcpad);

  /* ffmpeg objects */
  ffmpegenc->context = avcodec_alloc_context();
  ffmpegenc->picture = avcodec_alloc_frame();
  ffmpegenc->opened = FALSE;
  ffmpegenc->cache = NULL;

  if (oclass->in_plugin->type == CODEC_TYPE_VIDEO) {
    gst_pad_set_chain_function (ffmpegenc->sinkpad, gst_ffmpegenc_chain_video);

    ffmpegenc->bitrate = 300000;
    ffmpegenc->buffer_size = 512 * 1024;
    ffmpegenc->gop_size = 15;
  } else if (oclass->in_plugin->type == CODEC_TYPE_AUDIO) {
    gst_pad_set_chain_function (ffmpegenc->sinkpad, gst_ffmpegenc_chain_audio);

    ffmpegenc->bitrate = 128000;
  }
}

static void
gst_ffmpegenc_dispose (GObject *object)
{
  GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *) object;

  /* close old session */
  if (ffmpegenc->opened) {
    avcodec_close (ffmpegenc->context);
    ffmpegenc->opened = FALSE;
  }

  /* clean up remaining allocated data */
  av_free (ffmpegenc->context);
  av_free (ffmpegenc->picture);
}

static GstPadLinkReturn
gst_ffmpegenc_connect (GstPad  *pad,
		       const GstCaps *caps)
{
  GstCaps *other_caps;
  GstCaps *allowed_caps;
  GstCaps *icaps;
  enum PixelFormat pix_fmt;
  GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *) gst_pad_get_parent (pad);
  GstFFMpegEncClass *oclass = (GstFFMpegEncClass *) G_OBJECT_GET_CLASS(ffmpegenc);

  /* close old session */
  if (ffmpegenc->opened) {
    avcodec_close (ffmpegenc->context);
    ffmpegenc->opened = FALSE;
  }

  /* set defaults */
  avcodec_get_context_defaults (ffmpegenc->context);

  /* user defined properties */
  ffmpegenc->context->bit_rate = ffmpegenc->bitrate;
  ffmpegenc->context->bit_rate_tolerance = ffmpegenc->bitrate;
  ffmpegenc->context->gop_size = ffmpegenc->gop_size;
  ffmpegenc->context->me_method = ffmpegenc->me_method;

  /* general properties */
  ffmpegenc->context->qmin = 3;
  ffmpegenc->context->qmax = 15;
  ffmpegenc->context->max_qdiff = 3;

  /* no edges */
  ffmpegenc->context->flags |= CODEC_FLAG_EMU_EDGE;

  /* fetch pix_fmt and so on */
  gst_ffmpeg_caps_to_codectype (oclass->in_plugin->type,
				caps, ffmpegenc->context);

  pix_fmt = ffmpegenc->context->pix_fmt;

  /* open codec */
  if (avcodec_open (ffmpegenc->context, oclass->in_plugin) < 0) {
    avcodec_close (ffmpegenc->context);
    GST_DEBUG ("ffenc_%s: Failed to open FFMPEG codec",
	       oclass->in_plugin->name);
    return GST_PAD_LINK_REFUSED;
  }

  /* is the colourspace correct? */
  if (pix_fmt != ffmpegenc->context->pix_fmt) {
    avcodec_close (ffmpegenc->context);
    GST_DEBUG ("ffenc_%s: AV wants different colourspace (%d given, %d wanted)",
	       oclass->in_plugin->name, pix_fmt, ffmpegenc->context->pix_fmt);
    return GST_PAD_LINK_REFUSED;
  }

  /* try to set this caps on the other side */
  other_caps = gst_ffmpeg_codecid_to_caps (oclass->in_plugin->id,
					   ffmpegenc->context, TRUE);
  if (!other_caps) {
    avcodec_close (ffmpegenc->context);
    GST_DEBUG ("Unsupported codec - no caps found");
    return GST_PAD_LINK_REFUSED;
  }

  allowed_caps = gst_pad_get_allowed_caps (ffmpegenc->srcpad);
  icaps = gst_caps_intersect (allowed_caps, other_caps);
  gst_caps_free (allowed_caps);
  gst_caps_free (other_caps);

  if (gst_caps_is_empty (icaps)) {
    gst_caps_free (icaps);
    return GST_PAD_LINK_REFUSED;
  }

  if (gst_caps_get_size (icaps) > 1) {
    GstCaps *newcaps;

    newcaps = gst_caps_new_full (gst_structure_copy (gst_caps_get_structure (icaps, 0)), NULL);
    gst_caps_free (icaps);
    icaps = newcaps;
  }

  /* FIXME set_explicit_caps is not supposed to be used in a pad link
   * function. */
  if (!gst_pad_set_explicit_caps (ffmpegenc->srcpad, icaps)) {
    avcodec_close (ffmpegenc->context);
    gst_caps_free (icaps);
    return GST_PAD_LINK_REFUSED;
  }
  gst_caps_free (icaps);

  /* success! */
  ffmpegenc->opened = TRUE;

  return GST_PAD_LINK_OK;
}

static void
gst_ffmpegenc_chain_video (GstPad  *pad,
			   GstData *_data)
{
  GstBuffer *inbuf = GST_BUFFER (_data);
  GstBuffer *outbuf = NULL;
  GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *)(gst_pad_get_parent (pad));
  GstFFMpegEncClass *oclass = (GstFFMpegEncClass*)(G_OBJECT_GET_CLASS(ffmpegenc));
  gint ret_size = 0;

  /* FIXME: events (discont (flush!) and eos (close down) etc.) */

  outbuf = gst_buffer_new_and_alloc (ffmpegenc->buffer_size);
  avpicture_fill ((AVPicture *) ffmpegenc->picture,
		  GST_BUFFER_DATA (inbuf),
		  ffmpegenc->context->pix_fmt,
		  ffmpegenc->context->width,
		  ffmpegenc->context->height);
  ffmpegenc->picture->pts = GST_BUFFER_TIMESTAMP (inbuf) / 1000;
  ret_size = avcodec_encode_video (ffmpegenc->context,
				   GST_BUFFER_DATA (outbuf),
				   GST_BUFFER_MAXSIZE (outbuf),
				   ffmpegenc->picture);

  if (ret_size < 0) {
    g_warning("ffenc_%s: failed to encode buffer",
	      oclass->in_plugin->name);
    gst_buffer_unref (inbuf);
    return;
  }

  GST_BUFFER_SIZE (outbuf) = ret_size;
  GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (inbuf);
  GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (inbuf);
  gst_pad_push (ffmpegenc->srcpad, GST_DATA (outbuf));

  gst_buffer_unref (inbuf);
}

static void
gst_ffmpegenc_chain_audio (GstPad  *pad,
			   GstData *_data)
{
  GstBuffer *inbuf = GST_BUFFER (_data);
  GstBuffer *outbuf = NULL, *subbuf;
  GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *)(gst_pad_get_parent (pad));
  GstFFMpegEncClass *oclass = (GstFFMpegEncClass*)(G_OBJECT_GET_CLASS(ffmpegenc));
  gint size, ret_size = 0, in_size, frame_size;

  size = GST_BUFFER_SIZE (inbuf);

  /* FIXME: events (discont (flush!) and eos (close down) etc.) */

  frame_size = ffmpegenc->context->frame_size * 2 *
			ffmpegenc->context->channels;
  in_size = size;
  if (ffmpegenc->cache)
    in_size += GST_BUFFER_SIZE (ffmpegenc->cache);

  while (1) {
    /* do we have enough data for one frame? */
    if (in_size / (2 * ffmpegenc->context->channels) <
	  ffmpegenc->context->frame_size) {
      if (in_size > size) {
        /* this is panic! we got a buffer, but still don't have enough
         * data. Merge them and retry in the next cycle... */
        ffmpegenc->cache = gst_buffer_merge (ffmpegenc->cache, inbuf);
      } else if (in_size == size) {
        /* exactly the same! how wonderful */
        ffmpegenc->cache = inbuf;
      } else if (in_size > 0) {
        ffmpegenc->cache = gst_buffer_create_sub (inbuf, size - in_size,
						  in_size);
        GST_BUFFER_DURATION (ffmpegenc->cache) =
	  GST_BUFFER_DURATION (inbuf) * GST_BUFFER_SIZE (ffmpegenc->cache) / size;
        GST_BUFFER_TIMESTAMP (ffmpegenc->cache) =
	  GST_BUFFER_TIMESTAMP (inbuf) + (GST_BUFFER_DURATION (inbuf) *
	    (size - in_size) / size);
        gst_buffer_unref (inbuf);
      } else {
        gst_buffer_unref (inbuf);
      }
          
      return;
    }

    /* create the frame */
    if (in_size > size) {
      /* merge */
      subbuf = gst_buffer_create_sub (inbuf, 0, frame_size - (in_size - size));
      GST_BUFFER_DURATION (subbuf) =
	GST_BUFFER_DURATION (inbuf) * GST_BUFFER_SIZE (subbuf) / size;
      subbuf = gst_buffer_merge (ffmpegenc->cache, subbuf);
      ffmpegenc->cache = NULL;
    } else {
      subbuf = gst_buffer_create_sub (inbuf, size - in_size, frame_size);
      GST_BUFFER_DURATION (subbuf) =
	GST_BUFFER_DURATION (inbuf) * GST_BUFFER_SIZE (subbuf) / size;
      GST_BUFFER_TIMESTAMP (subbuf) =
	GST_BUFFER_TIMESTAMP (inbuf) + (GST_BUFFER_DURATION (inbuf) *
	  (size - in_size) / size);
    }

    outbuf = gst_buffer_new_and_alloc (GST_BUFFER_SIZE (inbuf));
    ret_size = avcodec_encode_audio (ffmpegenc->context,
				     GST_BUFFER_DATA (outbuf),
				     GST_BUFFER_MAXSIZE (outbuf),
				     (const short int *)
				       GST_BUFFER_DATA (subbuf));

    if (ret_size < 0) {
      g_warning("ffenc_%s: failed to encode buffer",
		oclass->in_plugin->name);
      gst_buffer_unref (inbuf);
      gst_buffer_unref (outbuf);
      gst_buffer_unref (subbuf);
      return;
    }

    GST_BUFFER_SIZE (outbuf) = ret_size;
    GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (subbuf);
    GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (subbuf);
    gst_pad_push (ffmpegenc->srcpad, GST_DATA (outbuf));

    in_size -= frame_size;
    gst_buffer_unref (subbuf);
  }
}

static void
gst_ffmpegenc_set_property (GObject      *object,
			    guint         prop_id,
			    const GValue *value,
			    GParamSpec   *pspec)
{
  GstFFMpegEnc *ffmpegenc;

  /* Get a pointer of the right type. */
  ffmpegenc = (GstFFMpegEnc *)(object);

  /* Check the argument id to see which argument we're setting. */
  switch (prop_id) {
    case ARG_BIT_RATE:
      ffmpegenc->bitrate = g_value_get_ulong (value);
      break;
    case ARG_GOP_SIZE:
      ffmpegenc->gop_size = g_value_get_int (value);
      break;
    case ARG_ME_METHOD:
      ffmpegenc->me_method = g_value_get_enum (value);
      break;
    case ARG_BUFSIZE:
      ffmpegenc->buffer_size = g_value_get_ulong(value);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

/* The set function is simply the inverse of the get fuction. */
static void
gst_ffmpegenc_get_property (GObject    *object,
			    guint       prop_id,
			    GValue     *value,
			    GParamSpec *pspec)
{
  GstFFMpegEnc *ffmpegenc;

  /* It's not null if we got it, but it might not be ours */
  ffmpegenc = (GstFFMpegEnc *)(object);

  switch (prop_id) {
    case ARG_BIT_RATE:
      g_value_set_ulong (value, ffmpegenc->bitrate);
      break;
    case ARG_GOP_SIZE:
      g_value_set_int (value, ffmpegenc->gop_size);
      break;
    case ARG_ME_METHOD:
      g_value_set_enum (value, ffmpegenc->me_method);
      break;
    case ARG_BUFSIZE:
      g_value_set_ulong (value, ffmpegenc->buffer_size);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static GstElementStateReturn
gst_ffmpegenc_change_state (GstElement *element)
{
  GstFFMpegEnc *ffmpegenc = (GstFFMpegEnc *) element;
  gint transition = GST_STATE_TRANSITION (element);

  switch (transition) {
    case GST_STATE_PAUSED_TO_READY:
      if (ffmpegenc->opened) {
        avcodec_close (ffmpegenc->context);
        ffmpegenc->opened = FALSE;
      }
      if (ffmpegenc->cache) {
        gst_buffer_unref (ffmpegenc->cache);
        ffmpegenc->cache = NULL;
      }
      break;
  }

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

  return GST_STATE_SUCCESS;
}

gboolean
gst_ffmpegenc_register (GstPlugin *plugin)
{
  GTypeInfo typeinfo = {
    sizeof(GstFFMpegEncClass),      
    (GBaseInitFunc)gst_ffmpegenc_base_init,
    NULL,
    (GClassInitFunc)gst_ffmpegenc_class_init,
    NULL,
    NULL,
    sizeof(GstFFMpegEnc),
    0,
    (GInstanceInitFunc)gst_ffmpegenc_init,
  };
  GType type;
  AVCodec *in_plugin;
  
  in_plugin = first_avcodec;

  enc_global_plugins = g_hash_table_new (NULL, NULL);

  while (in_plugin) {
    gchar *type_name;
    GstCaps *srccaps, *sinkcaps;
    GstFFMpegEncClassParams *params;

    /* no quasi codecs, please */
    if (in_plugin->id == CODEC_ID_RAWVIDEO ||
	(in_plugin->id >= CODEC_ID_PCM_S16LE &&
	 in_plugin->id <= CODEC_ID_PCM_ALAW)) {
      goto next;
    }

    /* only encoders */
    if (!in_plugin->encode) {
      goto next;
    }

    /* first make sure we've got a supported type */
    srccaps = gst_ffmpeg_codecid_to_caps (in_plugin->id, NULL, TRUE);
    sinkcaps  = gst_ffmpeg_codectype_to_caps (in_plugin->type, NULL);
    if (!sinkcaps || !srccaps)
      goto next;

    /* construct the type */
    type_name = g_strdup_printf("ffenc_%s", in_plugin->name);

    /* if it's already registered, drop it */
    if (g_type_from_name(type_name)) {
      g_free(type_name);
      goto next;
    }

    params = g_new0 (GstFFMpegEncClassParams, 1);
    params->in_plugin = in_plugin;
    params->srccaps = srccaps;
    params->sinkcaps = sinkcaps;

    g_hash_table_insert (enc_global_plugins, 
		         GINT_TO_POINTER (0), 
			 (gpointer) params);

    /* create the glib type now */
    type = g_type_register_static(GST_TYPE_ELEMENT, type_name , &typeinfo, 0);
    if (!gst_element_register (plugin, type_name, GST_RANK_NONE, type)) {
      g_free (type_name);
      return FALSE;
    }

    g_free (type_name);

    g_hash_table_insert (enc_global_plugins, 
		         GINT_TO_POINTER (type), 
			 (gpointer) params);

next:
    in_plugin = in_plugin->next;
  }
  g_hash_table_remove (enc_global_plugins, GINT_TO_POINTER (0));

  return TRUE;
}