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ffmpeg/libavformat/flvdec.c

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/*
* FLV demuxer
* Copyright (c) 2003 The FFmpeg Project.
*
* This demuxer will generate a 1 byte extradata for VP6F content.
* It is composed of:
* - upper 4bits: difference between encoded width and visible width
* - lower 4bits: difference between encoded height and visible height
*
* 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 "avformat.h"
#include "flv.h"
static int flv_probe(AVProbeData *p)
{
const uint8_t *d;
d = p->buf;
if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0) {
return AVPROBE_SCORE_MAX;
}
return 0;
}
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
AVCodecContext *acodec = astream->codec;
switch(flv_codecid) {
//no distinction between S16 and S8 PCM codec flags
case FLV_CODECID_PCM:
acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 :
#ifdef WORDS_BIGENDIAN
CODEC_ID_PCM_S16BE;
#else
CODEC_ID_PCM_S16LE;
#endif
break;
case FLV_CODECID_PCM_LE:
acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
case FLV_CODECID_AAC : acodec->codec_id = CODEC_ID_AAC; break;
case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF; break;
case FLV_CODECID_SPEEX: acodec->codec_id = CODEC_ID_SPEEX; break;
case FLV_CODECID_MP3 : acodec->codec_id = CODEC_ID_MP3 ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
case FLV_CODECID_NELLYMOSER_8HZ_MONO:
acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
case FLV_CODECID_NELLYMOSER:
acodec->codec_id = CODEC_ID_NELLYMOSER;
break;
default:
av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
}
}
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
AVCodecContext *vcodec = vstream->codec;
switch(flv_codecid) {
case FLV_CODECID_H263 : vcodec->codec_id = CODEC_ID_FLV1 ; break;
case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
case FLV_CODECID_VP6 : vcodec->codec_id = CODEC_ID_VP6F ;
case FLV_CODECID_VP6A :
if(flv_codecid == FLV_CODECID_VP6A)
vcodec->codec_id = CODEC_ID_VP6A;
if(vcodec->extradata_size != 1) {
vcodec->extradata_size = 1;
vcodec->extradata = av_malloc(1);
}
vcodec->extradata[0] = get_byte(s->pb);
return 1; // 1 byte body size adjustment for flv_read_packet()
case FLV_CODECID_H264:
vcodec->codec_id = CODEC_ID_H264;
return 3; // not 4, reading packet type will consume one byte
default:
av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
vcodec->codec_tag = flv_codecid;
}
return 0;
}
static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
int length = get_be16(ioc);
if(length >= buffsize) {
url_fskip(ioc, length);
return -1;
}
get_buffer(ioc, buffer, length);
buffer[length] = '\0';
return length;
}
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, unsigned int max_pos, int depth) {
AVCodecContext *acodec, *vcodec;
ByteIOContext *ioc;
AMFDataType amf_type;
char str_val[256];
double num_val;
num_val = 0;
ioc = s->pb;
amf_type = get_byte(ioc);
switch(amf_type) {
case AMF_DATA_TYPE_NUMBER:
num_val = av_int2dbl(get_be64(ioc)); break;
case AMF_DATA_TYPE_BOOL:
num_val = get_byte(ioc); break;
case AMF_DATA_TYPE_STRING:
if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
return -1;
break;
case AMF_DATA_TYPE_OBJECT: {
unsigned int keylen;
while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
url_fskip(ioc, keylen); //skip key string
if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
return -1; //if we couldn't skip, bomb out.
}
if(get_byte(ioc) != AMF_END_OF_OBJECT)
return -1;
}
break;
case AMF_DATA_TYPE_NULL:
case AMF_DATA_TYPE_UNDEFINED:
case AMF_DATA_TYPE_UNSUPPORTED:
break; //these take up no additional space
case AMF_DATA_TYPE_MIXEDARRAY:
url_fskip(ioc, 4); //skip 32-bit max array index
while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
//this is the only case in which we would want a nested parse to not skip over the object
if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
return -1;
}
if(get_byte(ioc) != AMF_END_OF_OBJECT)
return -1;
break;
case AMF_DATA_TYPE_ARRAY: {
unsigned int arraylen, i;
arraylen = get_be32(ioc);
for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
return -1; //if we couldn't skip, bomb out.
}
}
break;
case AMF_DATA_TYPE_DATE:
url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
break;
default: //unsupported type, we couldn't skip
return -1;
}
if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
acodec = astream ? astream->codec : NULL;
vcodec = vstream ? vstream->codec : NULL;
if(amf_type == AMF_DATA_TYPE_BOOL) {
if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
} else if(amf_type == AMF_DATA_TYPE_NUMBER) {
if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
// else if(!strcmp(key, "width") && vcodec && num_val > 0) vcodec->width = num_val;
// else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
flv_set_video_codec(s, vstream, (int)num_val);
else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
acodec->bits_per_sample = num_val;
//we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
acodec->codec_id = CODEC_ID_PCM_S8;
}
else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
//some tools, like FLVTool2, write consistently approximate metadata sample rates
if (!acodec->sample_rate) {
switch((int)num_val) {
case 44000: acodec->sample_rate = 44100 ; break;
case 22000: acodec->sample_rate = 22050 ; break;
case 11000: acodec->sample_rate = 11025 ; break;
case 5000 : acodec->sample_rate = 5512 ; break;
default : acodec->sample_rate = num_val;
}
}
}
}
}
return 0;
}
static int flv_read_metabody(AVFormatContext *s, unsigned int next_pos) {
AMFDataType type;
AVStream *stream, *astream, *vstream;
ByteIOContext *ioc;
int i, keylen;
char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
astream = NULL;
vstream = NULL;
keylen = 0;
ioc = s->pb;
//first object needs to be "onMetaData" string
type = get_byte(ioc);
if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
return -1;
//find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
for(i = 0; i < s->nb_streams; i++) {
stream = s->streams[i];
if (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
}
//parse the second object (we want a mixed array)
if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
return -1;
return 0;
}
static AVStream *create_stream(AVFormatContext *s, int is_audio){
AVStream *st = av_new_stream(s, is_audio);
if (!st)
return NULL;
st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
return st;
}
static int flv_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
int offset, flags;
url_fskip(s->pb, 4);
flags = get_byte(s->pb);
/* old flvtool cleared this field */
/* FIXME: better fix needed */
if (!flags) {
flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
}
if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
!= (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
s->ctx_flags |= AVFMTCTX_NOHEADER;
if(flags & FLV_HEADER_FLAG_HASVIDEO){
if(!create_stream(s, 0))
return AVERROR(ENOMEM);
}
if(flags & FLV_HEADER_FLAG_HASAUDIO){
if(!create_stream(s, 1))
return AVERROR(ENOMEM);
}
offset = get_be32(s->pb);
url_fseek(s->pb, offset, SEEK_SET);
s->start_time = 0;
return 0;
}
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
{
av_free(st->codec->extradata);
st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!st->codec->extradata)
return AVERROR(ENOMEM);
st->codec->extradata_size = size;
get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
return 0;
}
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret, i, type, size, flags, is_audio, next, pos;
unsigned dts;
AVStream *st = NULL;
retry:
for(;;){
pos = url_ftell(s->pb);
url_fskip(s->pb, 4); /* size of previous packet */
type = get_byte(s->pb);
size = get_be24(s->pb);
dts = get_be24(s->pb);
dts |= get_byte(s->pb) << 24;
// av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
if (url_feof(s->pb))
return AVERROR(EIO);
url_fskip(s->pb, 3); /* stream id, always 0 */
flags = 0;
if(size == 0)
continue;
next= size + url_ftell(s->pb);
if (type == FLV_TAG_TYPE_AUDIO) {
is_audio=1;
flags = get_byte(s->pb);
size--;
} else if (type == FLV_TAG_TYPE_VIDEO) {
is_audio=0;
flags = get_byte(s->pb);
size--;
if ((flags & 0xf0) == 0x50) /* video info / command frame */
goto skip;
} else {
if (type == FLV_TAG_TYPE_META && size > 13+1+4)
flv_read_metabody(s, next);
else /* skip packet */
av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
skip:
url_fseek(s->pb, next, SEEK_SET);
continue;
}
/* skip empty data packets */
if (!size)
continue;
/* now find stream */
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
if (st->id == is_audio)
break;
}
if(i == s->nb_streams){
av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
st= create_stream(s, is_audio);
s->ctx_flags &= ~AVFMTCTX_NOHEADER;
}
// av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
if( (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || is_audio))
||(st->discard >= AVDISCARD_BIDIR && ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
|| st->discard >= AVDISCARD_ALL
){
url_fseek(s->pb, next, SEEK_SET);
continue;
}
if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
break;
}
// if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
int size;
const int pos= url_ftell(s->pb);
const int fsize= url_fsize(s->pb);
url_fseek(s->pb, fsize-4, SEEK_SET);
size= get_be32(s->pb);
url_fseek(s->pb, fsize-3-size, SEEK_SET);
if(size == get_be24(s->pb) + 11){
s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
}
url_fseek(s->pb, pos, SEEK_SET);
}
if(is_audio){
if(!st->codec->sample_rate || !st->codec->bits_per_sample || (!st->codec->codec_id && !st->codec->codec_tag)) {
st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
if((flags & FLV_AUDIO_CODECID_MASK) == FLV_CODECID_NELLYMOSER_8HZ_MONO)
st->codec->sample_rate= 8000;
else
st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
st->codec->bits_per_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
}
}else{
size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
}
if (st->codec->codec_id == CODEC_ID_AAC ||
st->codec->codec_id == CODEC_ID_H264) {
int type = get_byte(s->pb);
size--;
if (st->codec->codec_id == CODEC_ID_H264) {
// cts offset ignored because it might to be signed
// and would cause pts < dts
get_be24(s->pb);
}
if (type == 0) {
if ((ret = flv_get_extradata(s, st, size)) < 0)
return ret;
goto retry;
}
}
ret= av_get_packet(s->pb, pkt, size);
if (ret <= 0) {
return AVERROR(EIO);
}
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
pkt->dts = dts;
pkt->stream_index = st->index;
if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
pkt->flags |= PKT_FLAG_KEY;
return ret;
}
AVInputFormat flv_demuxer = {
"flv",
NULL_IF_CONFIG_SMALL("FLV format"),
0,
flv_probe,
flv_read_header,
flv_read_packet,
.extensions = "flv",
.value = CODEC_ID_FLV1,
};
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