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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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mpegvideoparse: tweak codec parser API and adjust parser element
... to allow for more efficient parsing and (more) consistent parsing API among various codec parsers. Fixes #672701. Conflicts: gst/videoparsers/gstmpegvideoparse.c
This commit is contained in:
Mark Nauwelaerts
parent
29a947642e
commit
28f3858b94
4 changed files with 133 additions and 150 deletions
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@ -229,6 +229,7 @@ failed:
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}
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}
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/* @size and @offset are wrt current reader position */
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static inline guint
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scan_for_start_codes (const GstByteReader * reader, guint offset, guint size)
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{
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@ -245,7 +246,7 @@ scan_for_start_codes (const GstByteReader * reader, guint offset, guint size)
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data = reader->data + reader->byte + offset;
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while (i < (size - 4)) {
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while (i <= (size - 4)) {
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if (data[i + 2] > 1) {
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i += 3;
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} else if (data[i + 1]) {
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@ -257,7 +258,7 @@ scan_for_start_codes (const GstByteReader * reader, guint offset, guint size)
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}
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}
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if (i < (size - 4))
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if (i <= (size - 4))
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return offset + i;
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/* nothing found */
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@ -275,14 +276,14 @@ scan_for_start_codes (const GstByteReader * reader, guint offset, guint size)
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* Parses the MPEG 1/2 video bitstream contained in @data , and returns the
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* detect packets as a list of #GstMpegVideoTypeOffsetSize.
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*
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* Returns: a #GList of #GstMpegVideoTypeOffsetSize
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* Returns: TRUE if a packet start code was found
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*/
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GList *
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gst_mpeg_video_parse (const guint8 * data, gsize size, guint offset)
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gboolean
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gst_mpeg_video_parse (GstMpegVideoPacket * packet,
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const guint8 * data, gsize size, guint offset)
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{
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gint off, rsize;
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gint off;
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GstByteReader br;
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GList *ret = NULL;
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if (!initialized) {
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GST_DEBUG_CATEGORY_INIT (mpegvideo_parser_debug, "codecparsers_mpegvideo",
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@ -292,53 +293,42 @@ gst_mpeg_video_parse (const guint8 * data, gsize size, guint offset)
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if (size <= offset) {
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GST_DEBUG ("Can't parse from offset %d, buffer is to small", offset);
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return NULL;
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return FALSE;
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}
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size -= offset;
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gst_byte_reader_init (&br, &data[offset], size);
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off = scan_for_start_codes (&br, 0, size);
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if (off < 0) {
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GST_DEBUG ("No start code prefix in this buffer");
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return NULL;
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return FALSE;
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}
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while (off >= 0 && off + 3 < size) {
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GstMpegVideoTypeOffsetSize *codoffsize;
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if (gst_byte_reader_skip (&br, off + 3) == FALSE)
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goto failed;
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if (gst_byte_reader_get_uint8 (&br, &packet->type) == FALSE)
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goto failed;
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if (gst_byte_reader_skip (&br, off + 3) == FALSE)
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goto failed;
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packet->data = data;
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packet->offset = offset + off + 4;
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packet->size = -1;
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codoffsize = g_malloc (sizeof (GstMpegVideoTypeOffsetSize));
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if (gst_byte_reader_get_uint8 (&br, &codoffsize->type) == FALSE)
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goto failed;
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/* try to find end of packet */
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size -= off + 4;
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off = scan_for_start_codes (&br, 0, size);
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codoffsize->offset = gst_byte_reader_get_pos (&br) + offset;
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if (off > 0)
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packet->size = off;
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rsize = gst_byte_reader_get_remaining (&br);
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if (rsize == 0) {
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/* if there are no more bytes after the start code set the size to -1 */
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off = -1;
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} else {
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off = scan_for_start_codes (&br, 0, rsize);
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}
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codoffsize->size = off;
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ret = g_list_prepend (ret, codoffsize);
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codoffsize = ret->data;
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}
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return g_list_reverse (ret);
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return TRUE;
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failed:
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{
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GST_WARNING ("Failed to parse");
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return g_list_reverse (ret);
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return FALSE;
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}
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}
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@ -179,7 +179,7 @@ typedef struct _GstMpegVideoPictureHdr GstMpegVideoPictureHdr;
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typedef struct _GstMpegVideoGop GstMpegVideoGop;
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typedef struct _GstMpegVideoPictureExt GstMpegVideoPictureExt;
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typedef struct _GstMpegVideoQuantMatrixExt GstMpegVideoQuantMatrixExt;
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typedef struct _GstMpegVideoTypeOffsetSize GstMpegVideoTypeOffsetSize;
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typedef struct _GstMpegVideoPacket GstMpegVideoPacket;
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/**
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* GstMpegVideoSequenceHdr:
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@ -362,20 +362,24 @@ struct _GstMpegVideoGop
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/**
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* GstMpegVideoTypeOffsetSize:
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*
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* @type: the type of the packet that start at @offset
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* @data: the data containing the packet starting at @offset
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* @offset: the offset of the packet start in bytes, it is the exact, start of the packet, no sync code included
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* @size: The size in bytes of the packet or -1 if the end wasn't found. It is the exact size of the packet, no sync code included
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*
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* A structure that contains the type of a packet, its offset and its size
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*/
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struct _GstMpegVideoTypeOffsetSize
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struct _GstMpegVideoPacket
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{
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const guint8 *data;
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guint8 type;
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guint offset;
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gint size;
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};
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GList *gst_mpeg_video_parse (const guint8 * data, gsize size, guint offset);
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gboolean gst_mpeg_video_parse (GstMpegVideoPacket * packet,
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const guint8 * data, gsize size, guint offset);
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gboolean gst_mpeg_video_parse_sequence_header (GstMpegVideoSequenceHdr * params,
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const guint8 * data, gsize size, guint offset);
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@ -181,6 +181,8 @@ gst_mpegv_parse_reset_frame (GstMpegvParse * mpvparse)
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mpvparse->seq_offset = -1;
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mpvparse->pic_offset = -1;
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mpvparse->frame_repeat_count = 0;
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memset (mpvparse->ext_offsets, 0, sizeof (mpvparse->ext_offsets));
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mpvparse->ext_count = 0;
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}
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static void
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@ -227,18 +229,19 @@ static gboolean
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gst_mpegv_parse_process_config (GstMpegvParse * mpvparse, GstBuffer * buf,
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guint size)
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{
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GList *tmp;
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guint8 *data;
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guint8 *data_with_prefix;
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GstMapInfo map;
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gst_buffer_map (buf, &map, GST_MAP_READ);
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data = map.data + mpvparse->seq_offset;
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if (mpvparse->seq_offset < 4) {
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/* This shouldn't happen, but just in case... */
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GST_WARNING_OBJECT (mpvparse, "Sequence header start code missing.");
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return FALSE;
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}
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gst_buffer_map (buf, &map, GST_MAP_READ);
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data = map.data + mpvparse->seq_offset;
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g_assert (size <= map.size);
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/* pointer to sequence header data including the start code prefix -
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used for codec private data */
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data_with_prefix = data - 4;
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@ -254,7 +257,7 @@ gst_mpegv_parse_process_config (GstMpegvParse * mpvparse, GstBuffer * buf,
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}
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if (gst_mpeg_video_parse_sequence_header (&mpvparse->sequencehdr, data,
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map.size - mpvparse->seq_offset, 0)) {
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size - mpvparse->seq_offset, 0)) {
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if (mpvparse->fps_num == 0 || mpvparse->fps_den == 0) {
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mpvparse->fps_num = mpvparse->sequencehdr.fps_n;
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mpvparse->fps_den = mpvparse->sequencehdr.fps_d;
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@ -271,24 +274,19 @@ gst_mpegv_parse_process_config (GstMpegvParse * mpvparse, GstBuffer * buf,
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/* Set mpeg version, and parse sequence extension */
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if (mpvparse->mpeg_version <= 0) {
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GstMpegVideoTypeOffsetSize *tpoffsz;
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gint i, offset;
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mpvparse->mpeg_version = 1;
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for (tmp = mpvparse->typeoffsize; tmp; tmp = tmp->next) {
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tpoffsz = tmp->data;
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if (tpoffsz->type == GST_MPEG_VIDEO_PACKET_EXTENSION) {
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mpvparse->mpeg_version = 2;
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if (gst_mpeg_video_parse_sequence_extension (&mpvparse->sequenceext,
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map.data, map.size, tpoffsz->offset)) {
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mpvparse->fps_num =
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mpvparse->sequencehdr.fps_n * (mpvparse->sequenceext.fps_n_ext +
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1);
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mpvparse->fps_den =
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mpvparse->sequencehdr.fps_d * (mpvparse->sequenceext.fps_d_ext +
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1);
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}
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for (i = 0; i < mpvparse->ext_count; ++i) {
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offset = mpvparse->ext_offsets[i];
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mpvparse->mpeg_version = 2;
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if (offset < size &&
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gst_mpeg_video_parse_sequence_extension (&mpvparse->sequenceext,
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map.data, size, offset)) {
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mpvparse->fps_num =
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mpvparse->sequencehdr.fps_n * (mpvparse->sequenceext.fps_n_ext + 1);
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mpvparse->fps_den =
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mpvparse->sequencehdr.fps_d * (mpvparse->sequenceext.fps_d_ext + 1);
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}
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}
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}
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@ -435,7 +433,9 @@ gst_mpegv_parse_process_sc (GstMpegvParse * mpvparse,
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case GST_MPEG_VIDEO_PACKET_EXTENSION:
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GST_LOG_OBJECT (mpvparse, "startcode is VIDEO PACKET EXTENSION");
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parse_picture_extension (mpvparse, buf, off);
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packet = FALSE;
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if (mpvparse->ext_count < G_N_ELEMENTS (mpvparse->ext_offsets))
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mpvparse->ext_offsets[mpvparse->ext_count++] = off;
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/* fall-through */
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default:
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packet = FALSE;
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break;
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@ -444,6 +444,8 @@ gst_mpegv_parse_process_sc (GstMpegvParse * mpvparse,
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/* set size to avoid processing config again */
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if (mpvparse->seq_offset >= 0 && off != mpvparse->seq_offset &&
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!mpvparse->seq_size && packet) {
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/* should always be at start */
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g_assert (mpvparse->seq_offset <= 4);
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gst_mpegv_parse_process_config (mpvparse, buf, off - mpvparse->seq_offset);
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mpvparse->seq_size = off - mpvparse->seq_offset;
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}
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@ -485,7 +487,6 @@ update_frame_parsing_status (GstMpegvParse * mpvparse,
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}
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}
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static GstFlowReturn
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gst_mpegv_parse_handle_frame (GstBaseParse * parse,
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GstBaseParseFrame * frame, gint * skipsize)
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@ -493,121 +494,108 @@ gst_mpegv_parse_handle_frame (GstBaseParse * parse,
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GstMpegvParse *mpvparse = GST_MPEGVIDEO_PARSE (parse);
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GstBuffer *buf = frame->buffer;
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gboolean ret = FALSE;
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GList *tmp;
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gint off = 0, fsize = -1;
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gint off = 0;
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GstMpegVideoPacket packet;
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guint8 *data;
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gint size;
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GstMapInfo map;
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gsize buf_size;
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GstMpegVideoTypeOffsetSize *codoffsz;
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update_frame_parsing_status (mpvparse, frame);
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if (mpvparse->last_sc >= 0)
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off = mpvparse->last_sc;
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GST_LOG_OBJECT (mpvparse, "parsing at offset %d", off);
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gst_buffer_map (buf, &map, GST_MAP_READ);
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buf_size = map.size;
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mpvparse->typeoffsize = gst_mpeg_video_parse (map.data, map.size, off);
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gst_buffer_unmap (buf, &map);
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data = map.data;
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size = map.size;
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/* No sc found */
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if (mpvparse->typeoffsize == NULL) {
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GST_LOG_OBJECT (mpvparse, "no start code");
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*skipsize = gst_buffer_get_size (buf) - 3;
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goto end;
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retry:
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/* at least start code and subsequent byte */
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if (G_UNLIKELY (size < 5 + off))
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goto exit;
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/* if already found a previous start code, e.g. start of frame, go for next */
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if (mpvparse->last_sc >= 0) {
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off = mpvparse->last_sc;
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goto next;
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}
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codoffsz = mpvparse->typeoffsize->data;
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/* if initial start code not at start, arrange to make it so */
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if (mpvparse->last_sc < 0) {
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/* check for sane start code */
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for (tmp = mpvparse->typeoffsize; tmp; tmp = g_list_next (tmp)) {
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codoffsz = tmp->data;
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g_assert (codoffsz->offset >= 4);
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off = codoffsz->offset - 4;
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GST_LOG_OBJECT (mpvparse, "checking for valid start code at %d", off);
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/* hard-code to 4 to force initial check */
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if (gst_mpegv_parse_process_sc (mpvparse, buf, 4, codoffsz->type)) {
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if (off > 0) {
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GST_LOG_OBJECT (mpvparse, "skipping to start code at offset %d", off);
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gst_mpegv_parse_reset_frame (mpvparse);
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*skipsize = off;
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goto end;
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}
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/* got starting start code where we want it now */
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GST_LOG_OBJECT (mpvparse, "got valid start code");
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mpvparse->last_sc = 0;
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break;
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}
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/* avoid hard-code hack bite */
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gst_mpegv_parse_reset_frame (mpvparse);
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}
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if (!gst_mpeg_video_parse (&packet, data, size, off)) {
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/* didn't find anything that looks like a sync word, skip */
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GST_LOG_OBJECT (mpvparse, "no start code found");
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*skipsize = size - 3;
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goto exit;
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}
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if (mpvparse->last_sc < 0) {
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GST_LOG_OBJECT (mpvparse, "no valid start code");
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*skipsize = gst_buffer_get_size (buf) - 3;
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goto end;
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off = packet.offset - 4;
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GST_LOG_OBJECT (mpvparse, "possible sync at buffer offset %d", off);
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/* possible frame header, but not at offset 0? skip bytes before sync */
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if (G_UNLIKELY (off > 0)) {
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*skipsize = off;
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goto exit;
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}
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/* note: initial start code is assumed at offset 0 by subsequent code */
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/* examine start code, see if it looks like an initial start code */
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if (gst_mpegv_parse_process_sc (mpvparse, buf, 4, packet.type)) {
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/* found sc */
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GST_LOG_OBJECT (mpvparse, "valid start code found");
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mpvparse->last_sc = 0;
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} else {
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off++;
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gst_mpegv_parse_reset_frame (mpvparse);
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GST_LOG_OBJECT (mpvparse, "invalid start code");
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goto retry;
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}
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next:
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/* start is fine as of now */
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*skipsize = 0;
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/* initial packet processed above */
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for (tmp = mpvparse->typeoffsize; tmp; tmp = g_list_next (tmp)) {
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codoffsz = tmp->data;
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GST_LOG_OBJECT (mpvparse, "next start code at %d", codoffsz->offset);
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if (codoffsz->offset > 4)
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ret = gst_mpegv_parse_process_sc (mpvparse, buf, codoffsz->offset,
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codoffsz->type);
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else
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ret = FALSE;
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if (ret) {
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*skipsize = 0;
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fsize = codoffsz->offset - 4;
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break;
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}
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/* start here next time around */
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mpvparse->last_sc = codoffsz->offset - 4;
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}
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end:
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if (fsize > 0) {
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ret = TRUE;
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GST_LOG_OBJECT (mpvparse, "found frame of size %d", fsize);
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} else if (mpvparse->last_sc < 0) {
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ret = FALSE;
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GST_LOG_OBJECT (mpvparse, "skipping %d", *skipsize);
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} else if (GST_BASE_PARSE_DRAINING (parse)) {
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fsize = buf_size;
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ret = TRUE;
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GST_LOG_OBJECT (mpvparse, "no more data, assuming frame size %d", fsize);
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/* position a bit further than last sc */
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off++;
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/* so now we have start code at start of data; locate next start code */
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if (!gst_mpeg_video_parse (&packet, data, size, off)) {
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off = -1;
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} else {
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/* need some more data */
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/* request best next available */
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ret = FALSE;
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GST_LOG_OBJECT (mpvparse, "obtaining more data");
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g_assert (packet.offset >= 4);
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off = packet.offset - 4;
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}
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g_list_foreach (mpvparse->typeoffsize, (GFunc) g_free, NULL);
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g_list_free (mpvparse->typeoffsize);
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mpvparse->typeoffsize = NULL;
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GST_LOG_OBJECT (mpvparse, "next start code at %d", off);
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if (off < 0) {
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/* if draining, take all */
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if (GST_BASE_PARSE_DRAINING (parse)) {
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GST_LOG_OBJECT (mpvparse, "draining, accepting all data");
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off = size;
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ret = TRUE;
|
||||
} else {
|
||||
GST_LOG_OBJECT (mpvparse, "need more data");
|
||||
/* resume scan where we left it */
|
||||
/* need - 4 since off is incremented later on */
|
||||
mpvparse->last_sc = size - 4;
|
||||
/* request best next available */
|
||||
off = G_MAXUINT;
|
||||
goto exit;
|
||||
}
|
||||
} else {
|
||||
/* decide whether this startcode ends a frame */
|
||||
ret = gst_mpegv_parse_process_sc (mpvparse, buf, off + 4, packet.type);
|
||||
}
|
||||
|
||||
if (!ret)
|
||||
goto next;
|
||||
|
||||
exit:
|
||||
gst_buffer_unmap (buf, &map);
|
||||
|
||||
if (ret) {
|
||||
GstFlowReturn res;
|
||||
|
||||
*skipsize = 0;
|
||||
g_assert (fsize <= buf_size);
|
||||
g_assert (off <= map.size);
|
||||
res = gst_mpegv_parse_parse_frame (parse, frame);
|
||||
if (res == GST_BASE_PARSE_FLOW_DROPPED)
|
||||
frame->flags |= GST_BASE_PARSE_FRAME_FLAG_DROP;
|
||||
return gst_base_parse_finish_frame (parse, frame, fsize);
|
||||
return gst_base_parse_finish_frame (parse, frame, off);
|
||||
}
|
||||
|
||||
return GST_FLOW_OK;
|
||||
|
|
|
|||
|
|
@ -51,7 +51,8 @@ struct _GstMpegvParse {
|
|||
GstBaseParse element;
|
||||
|
||||
/* parse state */
|
||||
GList *typeoffsize;
|
||||
gint ext_offsets[10];
|
||||
gint ext_count;
|
||||
gint last_sc;
|
||||
gint seq_offset;
|
||||
gint seq_size;
|
||||
|
|
|
|||
Loading…
Reference in a new issue