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ffmpeg/libavformat/dv.c
Carl Eugen Hoyos 4d8875ec23 lavf: Constify the probe function argument. 
Reviewed-by: Lauri Kasanen
Reviewed-by: Tomas Härdin
2019-03-21 11:42:17 +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;
uint64_t abytes;
};
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, 1, 30000);
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_string(tc, AV_RB32(tc_pack + 1), prevent_df);
return 1;
}
/* The following 3 functions constitute our interface to the world */
DVDemuxContext *avpriv_dv_init_demux(AVFormatContext *s)
{
DVDemuxContext *c;
c = av_mallocz(sizeof(DVDemuxContext));
if (!c)
return NULL;
c->vst = avformat_new_stream(s, NULL);
if (!c->vst) {
av_free(c);
return NULL;
}
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 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->abytes * 30000 * 8 /
c->ast[i]->codecpar->bit_rate;
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;
c->abytes += size;
}
} else {
c->abytes += size;
}
/* 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;
if (c->ach) {
if (c->sys) {
c->abytes = av_rescale_q(c->frames, c->sys->time_base,
(AVRational) { 8, c->ast[0]->codecpar->bit_rate });
} else
av_log(c->fctx, AV_LOG_ERROR, "cannot adjust audio bytes\n");
}
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.
int partial_frame_size = 3 * 80;
uint8_t *partial_frame = av_mallocz(sizeof(*partial_frame) *
partial_frame_size);
RawDVContext *c = s->priv_data;
if (!partial_frame)
return AVERROR(ENOMEM);
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:
av_free(partial_frame);
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;
c->dv_demux = avpriv_dv_init_demux(s);
if (!c->dv_demux)
return -1;
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 -1;
}
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 -1;
}
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_read_close(AVFormatContext *s)
{
RawDVContext *c = s->priv_data;
av_freep(&c->dv_demux);
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_close = dv_read_close,
.read_seek = dv_read_seek,
.extensions = "dv,dif",
};
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