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ffmpeg/libavformat/dv.c

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/*
* General DV muxer/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) support
* Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
*
* 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 "dvdata.h"
#include "dv.h"
struct DVDemuxContext {
const DVprofile* sys; /* Current DV profile. E.g.: 525/60, 625/50 */
AVFormatContext* fctx;
AVStream* vst;
AVStream* ast[2];
AVPacket audio_pkt[2];
uint8_t audio_buf[2][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;
}
/*
* This is the dumbest implementation of all -- it simply looks at
* a fixed offset and if pack isn't there -- fails. We might want
* to have a fallback mechanism for complete search of missing packs.
*/
static const uint8_t* dv_extract_pack(uint8_t* frame, enum dv_pack_type t)
{
int offs;
switch (t) {
case dv_audio_source:
offs = (80*6 + 80*16*3 + 3);
break;
case dv_audio_control:
offs = (80*6 + 80*16*4 + 3);
break;
case dv_video_control:
offs = (80*5 + 48 + 5);
break;
default:
return NULL;
}
return (frame[offs] == t ? &frame[offs] : NULL);
}
/*
* There's a couple of assumptions being made here:
* 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
* We can pass them upwards when ffmpeg will be ready to deal with them.
* 2. We don't do software emphasis.
* 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
* are converted into 16bit linear ones.
*/
static int dv_extract_audio(uint8_t* frame, uint8_t* pcm, uint8_t* pcm2,
const DVprofile *sys)
{
int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
uint16_t lc, rc;
const uint8_t* as_pack;
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 - 32 kHz */
quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
if (quant > 1)
return -1; /* Unsupported quantization */
size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
half_ch = sys->difseg_size/2;
/* for each DIF channel */
for (chan = 0; chan < sys->n_difchan; chan++) {
/* 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 (12bit mode only) */
if (!pcm2)
break;
else
pcm = pcm2;
}
/* for each AV sequence */
for (j = 0; j < 9; j++) {
for (d = 8; d < 80; d += 2) {
if (quant == 0) { /* 16bit quantization */
of = sys->audio_shuffle[i][j] + (d - 8)/2 * sys->audio_stride;
if (of*2 >= size)
continue;
pcm[of*2] = frame[d+1]; // FIXME: may be we have to admit
pcm[of*2+1] = frame[d]; // that DV is a big endian PCM
if (pcm[of*2+1] == 0x80 && pcm[of*2] == 0x00)
pcm[of*2+1] = 0;
} else { /* 12bit 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;
pcm[of*2] = lc & 0xff; // FIXME: may be we have to admit
pcm[of*2+1] = lc >> 8; // that DV is a big endian PCM
of = sys->audio_shuffle[i%half_ch+half_ch][j] +
(d - 8)/3 * sys->audio_stride;
pcm[of*2] = rc & 0xff; // FIXME: may be we have to admit
pcm[of*2+1] = rc >> 8; // that DV is a big endian PCM
++d;
}
}
frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
}
}
/* next stereo channel (50Mbps only) */
if(!pcm2)
break;
pcm = pcm2;
}
return size;
}
static int dv_extract_audio_info(DVDemuxContext* c, 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 - 32 kHz */
stype = (as_pack[3] & 0x1f); /* 0 - 2CH, 2 - 4CH */
quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
/* note: ach counts PAIRS of channels (i.e. stereo channels) */
ach = (stype == 2 || (quant && (freq == 2))) ? 2 : 1;
/* Dynamic handling of the audio streams in DV */
for (i=0; i<ach; i++) {
if (!c->ast[i]) {
c->ast[i] = av_new_stream(c->fctx, 0);
if (!c->ast[i])
break;
av_set_pts_info(c->ast[i], 64, 1, 30000);
c->ast[i]->codec->codec_type = CODEC_TYPE_AUDIO;
c->ast[i]->codec->codec_id = 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 |= PKT_FLAG_KEY;
}
c->ast[i]->codec->sample_rate = dv_audio_frequency[freq];
c->ast[i]->codec->channels = 2;
c->ast[i]->codec->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, uint8_t* frame)
{
const uint8_t* vsc_pack;
AVCodecContext* avctx;
int apt, is16_9;
int size = 0;
if (c->sys) {
avctx = c->vst->codec;
av_set_pts_info(c->vst, 64, c->sys->frame_rate_base, c->sys->frame_rate);
avctx->time_base= (AVRational){c->sys->frame_rate_base, c->sys->frame_rate};
if(!avctx->width){
avctx->width = c->sys->width;
avctx->height = c->sys->height;
}
avctx->pix_fmt = c->sys->pix_fmt;
/* 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)));
avctx->sample_aspect_ratio = c->sys->sar[is16_9];
avctx->bit_rate = av_rescale(c->sys->frame_size * 8,
c->sys->frame_rate,
c->sys->frame_rate_base);
size = c->sys->frame_size;
}
return size;
}
/*
* The following 3 functions constitute our interface to the world
*/
DVDemuxContext* dv_init_demux(AVFormatContext *s)
{
DVDemuxContext *c;
c = av_mallocz(sizeof(DVDemuxContext));
if (!c)
return NULL;
c->vst = av_new_stream(s, 0);
if (!c->vst) {
av_free(c);
return NULL;
}
c->sys = NULL;
c->fctx = s;
c->ast[0] = c->ast[1] = NULL;
c->ach = 0;
c->frames = 0;
c->abytes = 0;
c->vst->codec->codec_type = CODEC_TYPE_VIDEO;
c->vst->codec->codec_id = CODEC_ID_DVVIDEO;
c->vst->codec->bit_rate = 25000000;
c->vst->start_time = 0;
return c;
}
int 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 dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
uint8_t* buf, int buf_size)
{
int size, i;
if (buf_size < DV_PROFILE_BYTES ||
!(c->sys = dv_frame_profile(buf)) ||
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].size = size;
c->audio_pkt[i].pts = c->abytes * 30000*8 / c->ast[i]->codec->bit_rate;
}
dv_extract_audio(buf, c->audio_buf[0], c->audio_buf[1], c->sys);
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->size = size;
pkt->flags |= PKT_FLAG_KEY;
pkt->stream_index = c->vst->id;
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 DVprofile* sys = dv_codec_profile(c->vst->codec);
int64_t offset;
int64_t size = url_fsize(&s->pb);
int64_t max_offset = ((size-1) / sys->frame_size) * sys->frame_size;
offset = sys->frame_size * timestamp;
if (offset > max_offset) offset = max_offset;
else if (offset < 0) offset = 0;
return offset;
}
void dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
{
c->frames= frame_offset;
if (c->ach)
c->abytes= av_rescale(c->frames,
c->ast[0]->codec->bit_rate * (int64_t)c->sys->frame_rate_base,
8*c->sys->frame_rate);
c->audio_pkt[0].size = c->audio_pkt[1].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_header(AVFormatContext *s,
AVFormatParameters *ap)
{
RawDVContext *c = s->priv_data;
c->dv_demux = dv_init_demux(s);
if (!c->dv_demux)
return -1;
if (get_buffer(&s->pb, c->buf, DV_PROFILE_BYTES) <= 0 ||
url_fseek(&s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
return AVERROR_IO;
c->dv_demux->sys = dv_frame_profile(c->buf);
s->bit_rate = av_rescale(c->dv_demux->sys->frame_size * 8,
c->dv_demux->sys->frame_rate,
c->dv_demux->sys->frame_rate_base);
return 0;
}
static int dv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int size;
RawDVContext *c = s->priv_data;
size = dv_get_packet(c->dv_demux, pkt);
if (size < 0) {
size = c->dv_demux->sys->frame_size;
if (get_buffer(&s->pb, c->buf, size) <= 0)
return AVERROR_IO;
size = dv_produce_packet(c->dv_demux, pkt, c->buf, size);
}
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);
dv_offset_reset(c, offset / c->sys->frame_size);
offset = url_fseek(&s->pb, offset, SEEK_SET);
return (offset < 0)?offset:0;
}
static int dv_read_close(AVFormatContext *s)
{
RawDVContext *c = s->priv_data;
av_free(c->dv_demux);
return 0;
}
#ifdef CONFIG_DV_DEMUXER
AVInputFormat dv_demuxer = {
"dv",
"DV video format",
sizeof(RawDVContext),
NULL,
dv_read_header,
dv_read_packet,
dv_read_close,
dv_read_seek,
.extensions = "dv,dif",
};
#endif
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