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Fix PTS rollover detection using per-stream state instead of shared s… #2131

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Fix PTS rollover detection using per-stream state instead of shared s… #2131

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1 change: 1 addition & 0 deletions src/lib_ccx/ccx_demuxer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -452,6 +452,7 @@ struct demuxer_data *alloc_demuxer_data(void)
data->len = 0;
data->pts = CCX_NOPTS;
data->rollover_bits = 0;
data->prev_pts_33 = 0;
data->tb.num = 1;
data->tb.den = 90000;
data->next_stream = 0;
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1 change: 1 addition & 0 deletions src/lib_ccx/ccx_demuxer.h
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Expand Up @@ -174,6 +174,7 @@ struct demuxer_data
unsigned char *buffer;
size_t len;
unsigned int rollover_bits; // The PTS rolls over every 26 hours and that can happen in the middle of a stream.
LLONG prev_pts_33; // Previous 33-bit PTS for this stream's rollover detection (per-stream, not shared)
LLONG pts;
struct ccx_rational tb;
struct demuxer_data *next_stream;
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9 changes: 4 additions & 5 deletions src/lib_ccx/stream_functions.c
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Expand Up @@ -297,7 +297,6 @@ int read_video_pes_header(struct ccx_demuxer *ctx, struct demuxer_data *data, un
long long result;
unsigned peslen = nextheader[4] << 8 | nextheader[5];
unsigned payloadlength = 0; // Length of packet data bytes
static LLONG current_pts_33 = 0; // Last PTS from the header, without rollover bits

if (!sbuflen)
{
Expand Down Expand Up @@ -437,14 +436,14 @@ int read_video_pes_header(struct ccx_demuxer *ctx, struct demuxer_data *data, un

if (data->pts != CCX_NOPTS) // Otherwise can't check for rollovers yet
{
if (!bits_9 && ((current_pts_33 >> 30) & 7) == 7) // PTS about to rollover
if (!bits_9 && ((data->prev_pts_33 >> 30) & 7) == 7) // PTS about to rollover
data->rollover_bits++;
if ((bits_9 >> 30) == 7 && ((current_pts_33 >> 30) & 7) == 0) // PTS rollback? Rare and if happens it would mean out of order frames
if ((bits_9 >> 30) == 7 && ((data->prev_pts_33 >> 30) & 7) == 0) // PTS rollback? Rare and if happens it would mean out of order frames
data->rollover_bits--;
}

current_pts_33 = bits_9 | bits_10 | bits_11 | bits_12 | bits_13;
data->pts = (LLONG)data->rollover_bits << 33 | current_pts_33;
data->prev_pts_33 = bits_9 | bits_10 | bits_11 | bits_12 | bits_13;
data->pts = (LLONG)data->rollover_bits << 33 | data->prev_pts_33;

/* The user data holding the captions seems to come between GOP and
* the first frame. The sync PTS (sync_pts) (set at picture 0)
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