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FFmpeg/libavformat/dv.c
Marton Balint 76fbb0052d avformat/dv: fix timestamps of audio packets in case of dropped corrupt audio frames 
By using the frame counter (and the video time base) for audio pts we lose some
timestamp precision but we ensure that video and audio coming from the same DV
frame are always in sync.

This patch also makes timestamps after seek consistent and it should also fix
the timestamps when the audio clock is unlocked and have a completely
indpendent clock source. (E.g. runs on fixed 48009 Hz which should have been
exact 48000 Hz)

Fixes out of sync timestamps in ticket #8762.

Signed-off-by: Marton Balint <cus@passwd.hu>
2020-12-06 18:09:24 +01:00

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/*
* General DV demuxer
* Copyright (c) 2003 Roman Shaposhnik
*
* Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
* of DV technical info.
*
* Raw DV format
* Copyright (c) 2002 Fabrice Bellard
*
* 50 Mbps (DVCPRO50) and 100 Mbps (DVCPRO HD) support
* Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
* Funded by BBC Research & Development
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <time.h>
#include "avformat.h"
#include "internal.h"
#include "libavcodec/dv_profile.h"
#include "libavcodec/dv.h"
#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/mathematics.h"
#include "libavutil/timecode.h"
#include "dv.h"
#include "libavutil/avassert.h"
struct DVDemuxContext {
const AVDVProfile* sys; /* Current DV profile. E.g.: 525/60, 625/50 */
AVFormatContext* fctx;
AVStream* vst;
AVStream* ast[4];
AVPacket audio_pkt[4];
uint8_t audio_buf[4][8192];
int ach;
int frames;
};
static inline uint16_t dv_audio_12to16(uint16_t sample)
{
uint16_t shift, result;
sample = (sample < 0x800) ? sample : sample | 0xf000;
shift = (sample & 0xf00) >> 8;
if (shift < 0x2 || shift > 0xd) {
result = sample;
} else if (shift < 0x8) {
shift--;
result = (sample - (256 * shift)) << shift;
} else {
shift = 0xe - shift;
result = ((sample + ((256 * shift) + 1)) << shift) - 1;
}
return result;
}
static const uint8_t *dv_extract_pack(const uint8_t *frame, enum dv_pack_type t)
{
int offs;
int c;
for (c = 0; c < 10; c++) {
switch (t) {
case dv_audio_source:
if (c&1) offs = (80 * 6 + 80 * 16 * 0 + 3 + c*12000);
else offs = (80 * 6 + 80 * 16 * 3 + 3 + c*12000);
break;
case dv_audio_control:
if (c&1) offs = (80 * 6 + 80 * 16 * 1 + 3 + c*12000);
else offs = (80 * 6 + 80 * 16 * 4 + 3 + c*12000);
break;
case dv_video_control:
if (c&1) offs = (80 * 3 + 8 + c*12000);
else offs = (80 * 5 + 48 + 5 + c*12000);
break;
case dv_timecode:
offs = (80*1 + 3 + 3);
break;
default:
return NULL;
}
if (frame[offs] == t)
break;
}
return frame[offs] == t ? &frame[offs] : NULL;
}
static const int dv_audio_frequency[3] = {
48000, 44100, 32000,
};
/*
* There's a couple of assumptions being made here:
* 1. By default we silence erroneous (0x8000/16-bit 0x800/12-bit) audio samples.
* We can pass them upwards when libavcodec will be ready to deal with them.
* 2. We don't do software emphasis.
* 3. Audio is always returned as 16-bit linear samples: 12-bit nonlinear samples
* are converted into 16-bit linear ones.
*/
static int dv_extract_audio(const uint8_t *frame, uint8_t **ppcm,
const AVDVProfile *sys)
{
int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
uint16_t lc, rc;
const uint8_t *as_pack;
uint8_t *pcm, ipcm;
as_pack = dv_extract_pack(frame, dv_audio_source);
if (!as_pack) /* No audio ? */
return 0;
smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
freq = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
quant = as_pack[4] & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */
if (quant > 1)
return -1; /* unsupported quantization */
if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
return AVERROR_INVALIDDATA;
size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
half_ch = sys->difseg_size / 2;
/* We work with 720p frames split in half, thus even frames have
* channels 0,1 and odd 2,3. */
ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
if (ipcm + sys->n_difchan > (quant == 1 ? 2 : 4)) {
av_log(NULL, AV_LOG_ERROR, "too many dv pcm frames\n");
return AVERROR_INVALIDDATA;
}
/* for each DIF channel */
for (chan = 0; chan < sys->n_difchan; chan++) {
av_assert0(ipcm<4);
pcm = ppcm[ipcm++];
if (!pcm)
break;
/* for each DIF segment */
for (i = 0; i < sys->difseg_size; i++) {
frame += 6 * 80; /* skip DIF segment header */
if (quant == 1 && i == half_ch) {
/* next stereo channel (12-bit mode only) */
av_assert0(ipcm<4);
pcm = ppcm[ipcm++];
if (!pcm)
break;
}
/* for each AV sequence */
for (j = 0; j < 9; j++) {
for (d = 8; d < 80; d += 2) {
if (quant == 0) { /* 16-bit quantization */
of = sys->audio_shuffle[i][j] +
(d - 8) / 2 * sys->audio_stride;
if (of * 2 >= size)
continue;
/* FIXME: maybe we have to admit that DV is a
* big-endian PCM */
pcm[of * 2] = frame[d + 1];
pcm[of * 2 + 1] = frame[d];
if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
pcm[of * 2 + 1] = 0;
} else { /* 12-bit quantization */
lc = ((uint16_t)frame[d] << 4) |
((uint16_t)frame[d + 2] >> 4);
rc = ((uint16_t)frame[d + 1] << 4) |
((uint16_t)frame[d + 2] & 0x0f);
lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
of = sys->audio_shuffle[i % half_ch][j] +
(d - 8) / 3 * sys->audio_stride;
if (of * 2 >= size)
continue;
/* FIXME: maybe we have to admit that DV is a
* big-endian PCM */
pcm[of * 2] = lc & 0xff;
pcm[of * 2 + 1] = lc >> 8;
of = sys->audio_shuffle[i % half_ch + half_ch][j] +
(d - 8) / 3 * sys->audio_stride;
/* FIXME: maybe we have to admit that DV is a
* big-endian PCM */
pcm[of * 2] = rc & 0xff;
pcm[of * 2 + 1] = rc >> 8;
++d;
}
}
frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
}
}
}
return size;
}
static int dv_extract_audio_info(DVDemuxContext *c, const uint8_t *frame)
{
const uint8_t *as_pack;
int freq, stype, smpls, quant, i, ach;
as_pack = dv_extract_pack(frame, dv_audio_source);
if (!as_pack || !c->sys) { /* No audio ? */
c->ach = 0;
return 0;
}
smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
freq = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
stype = as_pack[3] & 0x1f; /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
quant = as_pack[4] & 0x07; /* 0 - 16-bit linear, 1 - 12-bit nonlinear */
if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency)) {
av_log(c->fctx, AV_LOG_ERROR,
"Unrecognized audio sample rate index (%d)\n", freq);
return 0;
}
if (stype > 3) {
av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
c->ach = 0;
return 0;
}
/* note: ach counts PAIRS of channels (i.e. stereo channels) */
ach = ((int[4]) { 1, 0, 2, 4 })[stype];
if (ach == 1 && quant && freq == 2)
ach = 2;
/* Dynamic handling of the audio streams in DV */
for (i = 0; i < ach; i++) {
if (!c->ast[i]) {
c->ast[i] = avformat_new_stream(c->fctx, NULL);
if (!c->ast[i])
break;
avpriv_set_pts_info(c->ast[i], 64, c->sys->time_base.num, c->sys->time_base.den);
c->ast[i]->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
c->ast[i]->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
av_init_packet(&c->audio_pkt[i]);
c->audio_pkt[i].size = 0;
c->audio_pkt[i].data = c->audio_buf[i];
c->audio_pkt[i].stream_index = c->ast[i]->index;
c->audio_pkt[i].flags |= AV_PKT_FLAG_KEY;
}
c->ast[i]->codecpar->sample_rate = dv_audio_frequency[freq];
c->ast[i]->codecpar->channels = 2;
c->ast[i]->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
c->ast[i]->codecpar->bit_rate = 2 * dv_audio_frequency[freq] * 16;
c->ast[i]->start_time = 0;
}
c->ach = i;
return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
}
static int dv_extract_video_info(DVDemuxContext *c, const uint8_t *frame)
{
const uint8_t *vsc_pack;
AVCodecParameters *par;
int apt, is16_9;
par = c->vst->codecpar;
avpriv_set_pts_info(c->vst, 64, c->sys->time_base.num,
c->sys->time_base.den);
c->vst->avg_frame_rate = av_inv_q(c->vst->time_base);
/* finding out SAR is a little bit messy */
vsc_pack = dv_extract_pack(frame, dv_video_control);
apt = frame[4] & 0x07;
is16_9 = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
(!apt && (vsc_pack[2] & 0x07) == 0x07)));
c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
par->bit_rate = av_rescale_q(c->sys->frame_size,
(AVRational) { 8, 1 },
c->sys->time_base);
return c->sys->frame_size;
}
static int dv_extract_timecode(DVDemuxContext* c, const uint8_t* frame, char *tc)
{
const uint8_t *tc_pack;
// For PAL systems, drop frame bit is replaced by an arbitrary
// bit so its value should not be considered. Drop frame timecode
// is only relevant for NTSC systems.
int prevent_df = c->sys->ltc_divisor == 25 || c->sys->ltc_divisor == 50;
tc_pack = dv_extract_pack(frame, dv_timecode);
if (!tc_pack)
return 0;
av_timecode_make_smpte_tc_string2(tc, av_inv_q(c->sys->time_base), AV_RB32(tc_pack + 1), prevent_df, 1);
return 1;
}
/* The following 3 functions constitute our interface to the world */
static int dv_init_demux(AVFormatContext *s, DVDemuxContext *c)
{
c->vst = avformat_new_stream(s, NULL);
if (!c->vst)
return AVERROR(ENOMEM);
c->fctx = s;
c->vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
c->vst->codecpar->codec_id = AV_CODEC_ID_DVVIDEO;
c->vst->codecpar->bit_rate = 25000000;
c->vst->start_time = 0;
return 0;
}
DVDemuxContext *avpriv_dv_init_demux(AVFormatContext *s)
{
DVDemuxContext *c;
c = av_mallocz(sizeof(DVDemuxContext));
if (!c)
return NULL;
if (dv_init_demux(s, c)) {
av_free(c);
return NULL;
}
return c;
}
int avpriv_dv_get_packet(DVDemuxContext *c, AVPacket *pkt)
{
int size = -1;
int i;
for (i = 0; i < c->ach; i++) {
if (c->ast[i] && c->audio_pkt[i].size) {
*pkt = c->audio_pkt[i];
c->audio_pkt[i].size = 0;
size = pkt->size;
break;
}
}
return size;
}
int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
uint8_t *buf, int buf_size, int64_t pos)
{
int size, i;
uint8_t *ppcm[5] = { 0 };
if (buf_size < DV_PROFILE_BYTES ||
!(c->sys = av_dv_frame_profile(c->sys, buf, buf_size)) ||
buf_size < c->sys->frame_size) {
return -1; /* Broken frame, or not enough data */
}
/* Queueing audio packet */
/* FIXME: in case of no audio/bad audio we have to do something */
size = dv_extract_audio_info(c, buf);
for (i = 0; i < c->ach; i++) {
c->audio_pkt[i].pos = pos;
c->audio_pkt[i].size = size;
c->audio_pkt[i].pts = (c->sys->height == 720) ? (c->frames & ~1) : c->frames;
ppcm[i] = c->audio_buf[i];
}
if (c->ach)
dv_extract_audio(buf, ppcm, c->sys);
/* We work with 720p frames split in half, thus even frames have
* channels 0,1 and odd 2,3. */
if (c->sys->height == 720) {
if (buf[1] & 0x0C) {
c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
} else {
c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
}
}
/* Now it's time to return video packet */
size = dv_extract_video_info(c, buf);
av_init_packet(pkt);
pkt->data = buf;
pkt->pos = pos;
pkt->size = size;
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->stream_index = c->vst->index;
pkt->pts = c->frames;
c->frames++;
return size;
}
static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
int64_t timestamp, int flags)
{
// FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
const int frame_size = c->sys->frame_size;
int64_t offset;
int64_t size = avio_size(s->pb) - s->internal->data_offset;
int64_t max_offset = ((size - 1) / frame_size) * frame_size;
offset = frame_size * timestamp;
if (size >= 0 && offset > max_offset)
offset = max_offset;
else if (offset < 0)
offset = 0;
return offset + s->internal->data_offset;
}
void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
{
c->frames = frame_offset;
c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
}
/************************************************************
* Implementation of the easiest DV storage of all -- raw DV.
************************************************************/
typedef struct RawDVContext {
DVDemuxContext dv_demux;
uint8_t buf[DV_MAX_FRAME_SIZE];
} RawDVContext;
static int dv_read_timecode(AVFormatContext *s) {
int ret;
char timecode[AV_TIMECODE_STR_SIZE];
int64_t pos = avio_tell(s->pb);
// Read 3 DIF blocks: Header block and 2 Subcode blocks.
#define PARTIAL_FRAME_SIZE (3 * 80)
uint8_t partial_frame[PARTIAL_FRAME_SIZE];
RawDVContext *c = s->priv_data;
ret = avio_read(s->pb, partial_frame, PARTIAL_FRAME_SIZE);
if (ret < 0)
goto finish;
if (ret < PARTIAL_FRAME_SIZE) {
ret = -1;
goto finish;
}
ret = dv_extract_timecode(&c->dv_demux, partial_frame, timecode);
if (ret)
av_dict_set(&s->metadata, "timecode", timecode, 0);
else
av_log(s, AV_LOG_ERROR, "Detected timecode is invalid\n");
finish:
avio_seek(s->pb, pos, SEEK_SET);
return ret;
}
static int dv_read_header(AVFormatContext *s)
{
unsigned state, marker_pos = 0;
RawDVContext *c = s->priv_data;
int ret;
if ((ret = dv_init_demux(s, &c->dv_demux)) < 0)
return ret;
state = avio_rb32(s->pb);
while ((state & 0xffffff7f) != 0x1f07003f) {
if (avio_feof(s->pb)) {
av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
return AVERROR_INVALIDDATA;
}
if (state == 0x003f0700 || state == 0xff3f0700)
marker_pos = avio_tell(s->pb);
if (state == 0xff3f0701 && avio_tell(s->pb) - marker_pos == 80) {
avio_seek(s->pb, -163, SEEK_CUR);
state = avio_rb32(s->pb);
break;
}
state = (state << 8) | avio_r8(s->pb);
}
AV_WB32(c->buf, state);
if (avio_read(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) != DV_PROFILE_BYTES - 4 ||
avio_seek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0) {
return AVERROR(EIO);
}
c->dv_demux.sys = av_dv_frame_profile(c->dv_demux.sys,
c->buf,
DV_PROFILE_BYTES);
if (!c->dv_demux.sys) {
av_log(s, AV_LOG_ERROR,
"Can't determine profile of DV input stream.\n");
return AVERROR_INVALIDDATA;
}
s->bit_rate = av_rescale_q(c->dv_demux.sys->frame_size,
(AVRational) { 8, 1 },
c->dv_demux.sys->time_base);
if (s->pb->seekable & AVIO_SEEKABLE_NORMAL)
dv_read_timecode(s);
return 0;
}
static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int size;
RawDVContext *c = s->priv_data;
size = avpriv_dv_get_packet(&c->dv_demux, pkt);
if (size < 0) {
int ret;
int64_t pos = avio_tell(s->pb);
if (!c->dv_demux.sys)
return AVERROR(EIO);
size = c->dv_demux.sys->frame_size;
ret = avio_read(s->pb, c->buf, size);
if (ret < 0) {
return ret;
} else if (ret == 0) {
return AVERROR(EIO);
}
size = avpriv_dv_produce_packet(&c->dv_demux, pkt, c->buf, size, pos);
}
return size;
}
static int dv_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
RawDVContext *r = s->priv_data;
DVDemuxContext *c = &r->dv_demux;
int64_t offset = dv_frame_offset(s, c, timestamp, flags);
if (avio_seek(s->pb, offset, SEEK_SET) < 0)
return -1;
ff_dv_offset_reset(c, offset / c->sys->frame_size);
return 0;
}
static int dv_probe(const AVProbeData *p)
{
unsigned marker_pos = 0;
int i;
int matches = 0;
int firstmatch = 0;
int secondary_matches = 0;
if (p->buf_size < 5)
return 0;
for (i = 0; i < p->buf_size-4; i++) {
unsigned state = AV_RB32(p->buf+i);
if ((state & 0x0007f840) == 0x00070000) {
// any section header, also with seq/chan num != 0,
// should appear around every 12000 bytes, at least 10 per frame
if ((state & 0xff07ff7f) == 0x1f07003f) {
secondary_matches++;
if ((state & 0xffffff7f) == 0x1f07003f) {
matches++;
if (!i)
firstmatch = 1;
}
}
if (state == 0x003f0700 || state == 0xff3f0700)
marker_pos = i;
if (state == 0xff3f0701 && i - marker_pos == 80)
matches++;
}
}
if (matches && p->buf_size / matches < 1024 * 1024) {
if (matches > 4 || firstmatch ||
(secondary_matches >= 10 &&
p->buf_size / secondary_matches < 24000))
// not max to avoid dv in mov to match
return AVPROBE_SCORE_MAX * 3 / 4;
return AVPROBE_SCORE_MAX / 4;
}
return 0;
}
AVInputFormat ff_dv_demuxer = {
.name = "dv",
.long_name = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
.priv_data_size = sizeof(RawDVContext),
.read_probe = dv_probe,
.read_header = dv_read_header,
.read_packet = dv_read_packet,
.read_seek = dv_read_seek,
.extensions = "dv,dif",
};
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