Re-enable SVQ3, and also add a workaround for the fact that it writes to...

Re-enable SVQ3, and also add a workaround for the fact that it writes to (read-only) buffers. This effectively makes ...

Original commit message from CVS:
Re-enable SVQ3, and also add a workaround for the fact that it writes to (read-only) buffers. This effectively makes svq3 work

ext/ffmpeg/gstffmpegdec.c

@@ -344,9 +344,11 @@ gst_ffmpegdec_chain (GstPad    *pad,
 
     switch (oclass->in_plugin->type) {
       case CODEC_TYPE_VIDEO:
-	/* workaround:
-	   libavcodec/svq1.c:svq1_decode_frame writes to the given buffer */
-	if (oclass->in_plugin->id == CODEC_ID_SVQ1) {
+	/* workarounds, functions write to buffers:
+	   libavcodec/svq1.c:svq1_decode_frame writes to the given buffer.
+           libavcodec/svq3.c:svq3_decode_slice_header too */
+	if (oclass->in_plugin->id == CODEC_ID_SVQ1 ||
+            oclass->in_plugin->id == CODEC_ID_SVQ3) {
 	  inbuf = gst_buffer_copy_on_write(inbuf);
 	  data = GST_BUFFER_DATA (inbuf);
 	  size = GST_BUFFER_SIZE (inbuf);
@@ -480,7 +482,6 @@ gst_ffmpegdec_register (GstPlugin *plugin)
 
     /* no quasi-codecs, please */
     if (in_plugin->id == CODEC_ID_RAWVIDEO ||
-	in_plugin->id == CODEC_ID_SVQ3 || /* segfaults */
 	(in_plugin->id >= CODEC_ID_PCM_S16LE &&
 	 in_plugin->id <= CODEC_ID_PCM_ALAW)) {
       goto next;