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qtdemux: Split CEA608 buffers correctly so that each output buffer represents a single frame

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Sebastian Dröge 2018-12-20 12:14:46 +02:00 committed by Sebastian Dröge
parent aa65ea85f9
commit ec931601a6
1 changed files with 126 additions and 1 deletions
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127
gst/isomp4/qtdemux.c
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@ -349,6 +349,8 @@ struct _QtDemuxStream
/* buffer needs some custom processing, e.g. subtitles */
gboolean need_process;
/* buffer needs potentially be split, e.g. CEA608 subtitles */
gboolean need_split;
/* current position */
guint32 segment_index;
@ -5893,6 +5895,128 @@ exit:
return ret;
}
static GstFlowReturn
gst_qtdemux_split_and_push_buffer (GstQTDemux * qtdemux, QtDemuxStream * stream,
GstBuffer * buf)
{
GstFlowReturn ret = GST_FLOW_OK;
if (stream->subtype == FOURCC_clcp
&& CUR_STREAM (stream)->fourcc == FOURCC_c608 && stream->need_split) {
GstMapInfo map;
guint n_output_buffers, n_field1 = 0, n_field2 = 0;
guint n_triplets, i;
guint field1_off = 0, field2_off = 0;
/* We have to split CEA608 buffers so that each outgoing buffer contains
* one byte pair per field according to the framerate of the video track.
*
* If there is only a single byte pair per field we don't have to do
* anything
*/
gst_buffer_map (buf, &map, GST_MAP_READ);
n_triplets = map.size / 3;
for (i = 0; i < n_triplets; i++) {
if (map.data[3 * i] & 0x80)
n_field1++;
else
n_field2++;
}
g_assert (n_field1 || n_field2);
/* If there's more than 1 frame we have to split, otherwise we can just
* pass through */
if (n_field1 > 1 || n_field2 > 1) {
n_output_buffers =
gst_util_uint64_scale (GST_BUFFER_DURATION (buf),
CUR_STREAM (stream)->fps_n, GST_SECOND * CUR_STREAM (stream)->fps_d);
for (i = 0; i < n_output_buffers; i++) {
GstBuffer *outbuf =
gst_buffer_new_and_alloc ((n_field1 ? 3 : 0) + (n_field2 ? 3 : 0));
GstMapInfo outmap;
guint8 *outptr;
gst_buffer_map (outbuf, &outmap, GST_MAP_WRITE);
outptr = outmap.data;
if (n_field1) {
gboolean found = FALSE;
while (map.data + field1_off < map.data + map.size) {
if (map.data[field1_off] & 0x80) {
memcpy (outptr, &map.data[field1_off], 3);
field1_off += 3;
found = TRUE;
break;
}
field1_off += 3;
}
if (!found) {
const guint8 empty[] = { 0x80, 0x80, 0x80 };
memcpy (outptr, empty, 3);
}
outptr += 3;
}
if (n_field2) {
gboolean found = FALSE;
while (map.data + field2_off < map.data + map.size) {
if ((map.data[field2_off] & 0x80) == 0) {
memcpy (outptr, &map.data[field2_off], 3);
field2_off += 3;
found = TRUE;
break;
}
field2_off += 3;
}
if (!found) {
const guint8 empty[] = { 0x00, 0x80, 0x80 };
memcpy (outptr, empty, 3);
}
outptr += 3;
}
gst_buffer_unmap (outbuf, &outmap);
GST_BUFFER_PTS (outbuf) =
GST_BUFFER_PTS (buf) + gst_util_uint64_scale (i,
GST_SECOND * CUR_STREAM (stream)->fps_d,
CUR_STREAM (stream)->fps_n);
GST_BUFFER_DURATION (outbuf) =
gst_util_uint64_scale (GST_SECOND, CUR_STREAM (stream)->fps_d,
CUR_STREAM (stream)->fps_n);
GST_BUFFER_OFFSET (outbuf) = -1;
GST_BUFFER_OFFSET_END (outbuf) = -1;
ret = gst_qtdemux_push_buffer (qtdemux, stream, outbuf);
if (ret != GST_FLOW_OK && ret != GST_FLOW_NOT_LINKED)
break;
}
gst_buffer_unmap (buf, &map);
gst_buffer_unref (buf);
} else {
gst_buffer_unmap (buf, &map);
ret = gst_qtdemux_push_buffer (qtdemux, stream, buf);
}
} else {
ret = gst_qtdemux_push_buffer (qtdemux, stream, buf);
}
return ret;
}
/* Sets a buffer's attributes properly and pushes it downstream.
* Also checks for additional actions and custom processing that may
* need to be done first.
@ -6009,7 +6133,7 @@ gst_qtdemux_decorate_and_push_buffer (GstQTDemux * qtdemux,
}
#endif
ret = gst_qtdemux_push_buffer (qtdemux, stream, buf);
ret = gst_qtdemux_split_and_push_buffer (qtdemux, stream, buf);
exit:
return ret;
@ -15383,6 +15507,7 @@ qtdemux_sub_caps (GstQTDemux * qtdemux, QtDemuxStream * stream,
gst_caps_new_simple ("closedcaption/x-cea-608", "format",
G_TYPE_STRING, "s334-1a", NULL);
stream->need_process = TRUE;
stream->need_split = TRUE;
break;
case FOURCC_c708:
_codec ("CEA 708 Closed Caption");