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mpegts-mythtv.c: harmonize functions 1i ts->pos47 changes
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handle_packet (modified)

write_section_data (modified, change only to signature):
Harmonization doesn't break MHEG but it doesn't start as early,
so I have only modified the signature.

Now identical to FFmpeg's:
mpegts_get_dts
mpegts_get_pcr
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@ulmus-scott @bennettpeter
ulmus-scott authored and bennettpeter committed Aug 15, 2022
1 parent f6d361a commit f49fd8e
Showing 1 changed file with 82 additions and 44 deletions.
126 changes: 82 additions & 44 deletions mythtv/external/FFmpeg/libavformat/mpegts-mythtv.c
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Expand Up @@ -536,15 +536,16 @@ static int discard_pid(MpegTSContext *ts, unsigned int pid)
//ugly forward declaration
static void mpegts_push_section(MpegTSFilter *filter, const uint8_t *section, int section_len);

/** \fn write_section_data(AVFormatContext*,MpegTSFilter*,const uint8_t*,int,int)
/**
* Assemble PES packets out of TS packets, and then call the "section_cb"
* function when they are complete.
*
* NOTE: "DVB Section" is DVB terminology for an MPEG PES packet.
*/
static void write_section_data(AVFormatContext *s, MpegTSFilter *tss1,
static void write_section_data(MpegTSContext *ts, MpegTSFilter *tss1,
const uint8_t *buf, int buf_size, int is_start)
{
AVFormatContext *s = ts->stream;
MpegTSSectionFilter *tss = &tss1->u.section_filter;
int len;

Expand Down Expand Up @@ -2961,17 +2962,17 @@ static void sdt_cb(MpegTSFilter *filter, const uint8_t *section, int section_len
}
}

static int parse_pcr(int64_t *ppcr_high, int *ppcr_low,
const uint8_t *packet);

/* handle one TS packet */
static int handle_packet(MpegTSContext *ts, const uint8_t *packet, int64_t pos)
{
AVFormatContext *s = ts->stream;
MpegTSFilter *tss;
int len, pid, cc, expected_cc, cc_ok, afc, is_start, is_discontinuity,
has_adaptation, has_payload;
const uint8_t *p, *p_end;

pid = AV_RB16(packet + 1) & 0x1fff;

// MythTV PMT tracking in ffmpeg patch from danielk. https://github.com/MythTV/mythtv/commit/236872aa4dc73c45f01d71f749eb50eaf7eb12e4
if (!ts->pids[0]) {
/* make sure we're always scanning for new PAT's */
Expand All @@ -2980,98 +2981,132 @@ static int handle_packet(MpegTSContext *ts, const uint8_t *packet, int64_t pos)
}
// end MythTV

if(pid && discard_pid(ts, pid))
{
av_log(ts->stream, AV_LOG_INFO, "discarding pid %d\n", pid);
return 0;
}

pid = AV_RB16(packet + 1) & 0x1fff;
is_start = packet[1] & 0x40;
tss = ts->pids[pid];
if (ts->auto_guess && tss == NULL && is_start) {
if (ts->auto_guess && !tss && is_start) {
add_pes_stream(ts, pid, -1);
tss = ts->pids[pid];
}
if (!tss)
return 0;
if (is_start)
tss->discard = discard_pid(ts, pid);
if (tss->discard)
return 0;
ts->current_pid = pid;

afc = (packet[3] >> 4) & 3;
if (afc == 0) /* reserved value */
return 0;
has_adaptation = afc & 2;
has_payload = afc & 1;
is_discontinuity = has_adaptation
&& packet[4] != 0 /* with length > 0 */
&& (packet[5] & 0x80); /* and discontinuity indicated */
has_adaptation = afc & 2;
has_payload = afc & 1;
is_discontinuity = has_adaptation &&
packet[4] != 0 && /* with length > 0 */
(packet[5] & 0x80); /* and discontinuity indicated */

/* continuity check (currently not used) */
cc = (packet[3] & 0xf);
expected_cc = has_payload ? (tss->last_cc + 1) & 0x0f : tss->last_cc;
cc_ok = pid == 0x1FFF // null packet PID
|| is_discontinuity
|| tss->last_cc < 0
|| expected_cc == cc;
cc_ok = pid == 0x1FFF || // null packet PID
is_discontinuity ||
tss->last_cc < 0 ||
expected_cc == cc;

tss->last_cc = cc;
if (!cc_ok) {
av_log(ts->stream, AV_LOG_DEBUG,
"Continuity check failed for pid %d expected %d got %d\n",
pid, expected_cc, cc);
if(tss->type == MPEGTS_PES) {
if (tss->type == MPEGTS_PES) {
PESContext *pc = tss->u.pes_filter.opaque;
pc->flags |= AV_PKT_FLAG_CORRUPT;
}
}

if (packet[1] & 0x80) {
av_log(ts->stream, AV_LOG_DEBUG, "Packet had TEI flag set; marking as corrupt\n");
if (tss->type == MPEGTS_PES) {
PESContext *pc = tss->u.pes_filter.opaque;
pc->flags |= AV_PKT_FLAG_CORRUPT;
}
}

if (!has_payload)
return 0;
p = packet + 4;
if (has_adaptation) {
int64_t pcr_h;
int pcr_l;
if (parse_pcr(&pcr_h, &pcr_l, packet) == 0)
tss->last_pcr = pcr_h * 300 + pcr_l;
/* skip adaptation field */
p += p[0] + 1;
}
/* if past the end of packet, ignore */
p_end = packet + TS_PACKET_SIZE;
if (p >= p_end)
if (p >= p_end || !has_payload)
return 0;

pos = avio_tell(ts->stream->pb);
ts->pos47= pos % ts->raw_packet_size;
if (pos >= 0) {
av_assert0(pos >= TS_PACKET_SIZE);
ts->pos47_full = pos - TS_PACKET_SIZE;
}

if (tss->type == MPEGTS_SECTION) {
if (is_start) {
/* pointer field present */
len = *p++;
if (p + len > p_end)
{
av_log(s, AV_LOG_WARNING, "handle_packet: Last section data too long on PID=%#x, %d\n", pid, cc);
if (len > p_end - p)
return 0;
}
if (len && cc_ok) {
/* write remaining section bytes */
write_section_data(s, tss,
write_section_data(ts, tss,
p, len, 0);
/* check whether filter has been closed */
if (!ts->pids[pid])
return 0;
}
p += len;
if (p < p_end) {
write_section_data(s, tss,
write_section_data(ts, tss,
p, p_end - p, 1);
}
} else {
if (cc_ok) {
write_section_data(s, tss,
write_section_data(ts, tss,
p, p_end - p, 0);
}
}

// stop find_stream_info from waiting for more streams
// when all programs have received a PMT
if (ts->stream->ctx_flags & AVFMTCTX_NOHEADER && ts->scan_all_pmts <= 0) {
int i;
for (i = 0; i < ts->nb_prg; i++) {
if (!ts->prg[i].pmt_found)
break;
}
if (i == ts->nb_prg && ts->nb_prg > 0) {
int types = 0;
for (i = 0; i < ts->stream->nb_streams; i++) {
AVStream *st = ts->stream->streams[i];
if (st->codecpar->codec_type >= 0)
types |= 1<<st->codecpar->codec_type;
}
if ((types & (1<<AVMEDIA_TYPE_AUDIO) && types & (1<<AVMEDIA_TYPE_VIDEO)) || pos > 100000) {
av_log(ts->stream, AV_LOG_DEBUG, "All programs have pmt, headers found\n");
ts->stream->ctx_flags &= ~AVFMTCTX_NOHEADER;
}
}
}

} else {
int ret;
// Note: The position here points actually behind the current packet.
if ((ret = tss->u.pes_filter.pes_cb(tss, p, p_end - p, is_start,
pos - ts->raw_packet_size)) < 0)
return ret;
if (tss->type == MPEGTS_PES) {
if ((ret = tss->u.pes_filter.pes_cb(tss, p, p_end - p, is_start,
pos - ts->raw_packet_size)) < 0)
return ret;
}
}

return 0;
Expand Down Expand Up @@ -3578,22 +3613,25 @@ static int mpegts_read_close(AVFormatContext *s)
return 0;
}

#ifdef USE_SYNCPOINT_SEARCH
static int64_t mpegts_get_pcr(AVFormatContext *s, int stream_index,
static av_unused int64_t mpegts_get_pcr(AVFormatContext *s, int stream_index,
int64_t *ppos, int64_t pos_limit)
{
MpegTSContext *ts = s->priv_data;
int64_t pos, timestamp;
uint8_t buf[TS_PACKET_SIZE];
int pcr_l, pcr_pid = ((PESContext*)s->streams[stream_index]->priv_data)->pcr_pid;
pos = ((*ppos + ts->raw_packet_size - 1 - ts->pos47) / ts->raw_packet_size) * ts->raw_packet_size + ts->pos47;
int pcr_l, pcr_pid =
((PESContext *)s->streams[stream_index]->priv_data)->pcr_pid;
int pos47 = ts->pos47_full % ts->raw_packet_size;
pos =
((*ppos + ts->raw_packet_size - 1 - pos47) / ts->raw_packet_size) *
ts->raw_packet_size + pos47;
while(pos < pos_limit) {
if (avio_seek(s->pb, pos, SEEK_SET) < 0)
return AV_NOPTS_VALUE;
if (avio_read(s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE)
return AV_NOPTS_VALUE;
if (buf[0] != 0x47) {
if (mpegts_resync(s) < 0)
if (mpegts_resync(s, TS_PACKET_SIZE, buf) < 0)
return AV_NOPTS_VALUE;
pos = avio_tell(s->pb);
continue;
Expand All @@ -3608,15 +3646,15 @@ static int64_t mpegts_get_pcr(AVFormatContext *s, int stream_index,

return AV_NOPTS_VALUE;
}
#endif

static int64_t mpegts_get_dts(AVFormatContext *s, int stream_index,
int64_t *ppos, int64_t pos_limit)
{
MpegTSContext *ts = s->priv_data;
AVPacket *pkt;
int64_t pos;
pos = ((*ppos + ts->raw_packet_size - 1 - ts->pos47) / ts->raw_packet_size) * ts->raw_packet_size + ts->pos47;
int pos47 = ts->pos47_full % ts->raw_packet_size;
pos = ((*ppos + ts->raw_packet_size - 1 - pos47) / ts->raw_packet_size) * ts->raw_packet_size + pos47;
ff_read_frame_flush(s);
if (avio_seek(s->pb, pos, SEEK_SET) < 0)
return AV_NOPTS_VALUE;
Expand Down

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