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a712d725c0
ffmpeg/libavformat/nutenc.c
Michael Niedermayer a712d725c0 Header elision muxing support. 
This only removes 2 bytes from MP3 and MP2 currently.
Up to 4 could be removed from MP3/MP2 though this might need a 2pass muxer.
Primitive code to remove headers from MPEG-1/2/4 is there too but for the
single file I tried it on (the one in the regression tests), it was a loss
because all video frames were >4096 byte, so that it is disabled ATM.

Originally committed as revision 11936 to svn://svn.ffmpeg.org/ffmpeg/trunk
2008-02-15 02:57:19 +00:00

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/*
* nut muxer
* Copyright (c) 2004-2007 Michael Niedermayer
*
* 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 "nut.h"
#include "tree.h"
#include "mpegaudiodata.h"
static int find_expected_header(AVCodecContext *c, int size, int key_frame, uint8_t out[64]){
int sample_rate= c->sample_rate;
if(size>4096)
return 0;
AV_WB24(out, 1);
if(c->codec_id == CODEC_ID_MPEG4){
if(key_frame){
return 3;
}else{
out[3]= 0xB6;
return 4;
}
}else if(c->codec_id == CODEC_ID_MPEG1VIDEO || c->codec_id == CODEC_ID_MPEG2VIDEO){
return 3;
}else if(c->codec_id == CODEC_ID_H264){
return 3;
}else if(c->codec_id == CODEC_ID_MP3 || c->codec_id == CODEC_ID_MP2){
int lsf, mpeg25, sample_rate_index, bitrate_index, frame_size;
int layer= c->codec_id == CODEC_ID_MP3 ? 3 : 2;
unsigned int header= 0xFFF00000;
lsf = sample_rate < (24000+32000)/2;
mpeg25 = sample_rate < (12000+16000)/2;
sample_rate <<= lsf + mpeg25;
if (sample_rate < (32000 + 44100)/2) sample_rate_index=2;
else if(sample_rate < (44100 + 48000)/2) sample_rate_index=0;
else sample_rate_index=1;
sample_rate= ff_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25);
for(bitrate_index=2; bitrate_index<30; bitrate_index++){
frame_size = ff_mpa_bitrate_tab[lsf][layer-1][bitrate_index>>1];
frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
if(frame_size == size)
break;
}
header |= (!lsf)<<19;
header |= (4-layer)<<17;
header |= 1<<16; //no crc
AV_WB32(out, header);
if(size <= 0)
return 2; //we guess theres no crc, if there is one the user clearly doesnt care about overhead
if(bitrate_index == 30)
return -1; //something is wrong ...
header |= (bitrate_index>>1)<<12;
header |= sample_rate_index<<10;
header |= (bitrate_index&1)<<9;
return 2; //FIXME actually put the needed ones in build_elision_headers()
return 3; //we guess that the private bit isnt set
//FIXME the above asumtations should be checked, if these turn out false too often something should be done
}
return 0;
}
static int find_header_idx(AVFormatContext *s, AVCodecContext *c, int size, int frame_type){
NUTContext *nut = s->priv_data;
uint8_t out[64];
int i;
int len= find_expected_header(c, size, frame_type, out);
//av_log(NULL, AV_LOG_ERROR, "expected_h len=%d size=%d codec_id=%d\n", len, size, c->codec_id);
for(i=1; i<nut->header_count; i++){
if( len == nut->header_len[i]
&& !memcmp(out, nut->header[i], len)){
// av_log(NULL, AV_LOG_ERROR, "found %d\n", i);
return i;
}
}
// av_log(NULL, AV_LOG_ERROR, "nothing found\n");
return 0;
}
static void build_elision_headers(AVFormatContext *s){
NUTContext *nut = s->priv_data;
int i;
//FIXME this is lame
//FIXME write a 2pass mode to find the maximal headers
const static uint8_t headers[][5]={
{3, 0x00, 0x00, 0x01},
{4, 0x00, 0x00, 0x01, 0xB6},
{2, 0xFF, 0xFA}, //mp3+crc
{2, 0xFF, 0xFB}, //mp3
{2, 0xFF, 0xFC}, //mp2+crc
{2, 0xFF, 0xFD}, //mp2
};
nut->header_count= 7;
for(i=1; i<nut->header_count; i++){
nut->header_len[i]= headers[i-1][0];
nut->header [i]= &headers[i-1][1];
}
}
static void build_frame_code(AVFormatContext *s){
NUTContext *nut = s->priv_data;
int key_frame, index, pred, stream_id;
int start=1;
int end= 254;
int keyframe_0_esc= s->nb_streams > 2;
int pred_table[10];
FrameCode *ft;
ft= &nut->frame_code[start];
ft->flags= FLAG_CODED;
ft->size_mul=1;
ft->pts_delta=1;
start++;
if(keyframe_0_esc){
/* keyframe = 0 escape */
FrameCode *ft= &nut->frame_code[start];
ft->flags= FLAG_STREAM_ID | FLAG_SIZE_MSB | FLAG_CODED_PTS;
ft->size_mul=1;
start++;
}
for(stream_id= 0; stream_id<s->nb_streams; stream_id++){
int start2= start + (end-start)*stream_id / s->nb_streams;
int end2 = start + (end-start)*(stream_id+1) / s->nb_streams;
AVCodecContext *codec = s->streams[stream_id]->codec;
int is_audio= codec->codec_type == CODEC_TYPE_AUDIO;
int intra_only= /*codec->intra_only || */is_audio;
int pred_count;
for(key_frame=0; key_frame<2; key_frame++){
if(intra_only && keyframe_0_esc && key_frame==0)
continue;
{
FrameCode *ft= &nut->frame_code[start2];
ft->flags= FLAG_KEY*key_frame;
ft->flags|= FLAG_SIZE_MSB | FLAG_CODED_PTS;
ft->stream_id= stream_id;
ft->size_mul=1;
if(is_audio)
ft->header_idx= find_header_idx(s, codec, -1, key_frame);
start2++;
}
}
key_frame= intra_only;
#if 1
if(is_audio){
int frame_bytes= codec->frame_size*(int64_t)codec->bit_rate / (8*codec->sample_rate);
int pts;
for(pts=0; pts<2; pts++){
for(pred=0; pred<2; pred++){
FrameCode *ft= &nut->frame_code[start2];
ft->flags= FLAG_KEY*key_frame;
ft->stream_id= stream_id;
ft->size_mul=frame_bytes + 2;
ft->size_lsb=frame_bytes + pred;
ft->pts_delta=pts;
ft->header_idx= find_header_idx(s, codec, frame_bytes + pred, key_frame);
start2++;
}
}
}else{
FrameCode *ft= &nut->frame_code[start2];
ft->flags= FLAG_KEY | FLAG_SIZE_MSB;
ft->stream_id= stream_id;
ft->size_mul=1;
ft->pts_delta=1;
start2++;
}
#endif
if(codec->has_b_frames){
pred_count=5;
pred_table[0]=-2;
pred_table[1]=-1;
pred_table[2]=1;
pred_table[3]=3;
pred_table[4]=4;
}else if(codec->codec_id == CODEC_ID_VORBIS){
pred_count=3;
pred_table[0]=2;
pred_table[1]=9;
pred_table[2]=16;
}else{
pred_count=1;
pred_table[0]=1;
}
for(pred=0; pred<pred_count; pred++){
int start3= start2 + (end2-start2)*pred / pred_count;
int end3 = start2 + (end2-start2)*(pred+1) / pred_count;
for(index=start3; index<end3; index++){
FrameCode *ft= &nut->frame_code[index];
ft->flags= FLAG_KEY*key_frame;
ft->flags|= FLAG_SIZE_MSB;
ft->stream_id= stream_id;
//FIXME use single byte size and pred from last
ft->size_mul= end3-start3;
ft->size_lsb= index - start3;
ft->pts_delta= pred_table[pred];
if(is_audio)
ft->header_idx= find_header_idx(s, codec, -1, key_frame);
}
}
}
memmove(&nut->frame_code['N'+1], &nut->frame_code['N'], sizeof(FrameCode)*(255-'N'));
nut->frame_code[ 0].flags=
nut->frame_code[255].flags=
nut->frame_code['N'].flags= FLAG_INVALID;
}
/**
* Gets the length in bytes which is needed to store val as v.
*/
static int get_length(uint64_t val){
int i=1;
while(val>>=7)
i++;
return i;
}
static void put_v(ByteIOContext *bc, uint64_t val){
int i= get_length(val);
while(--i>0)
put_byte(bc, 128 | (val>>(7*i)));
put_byte(bc, val&127);
}
static void put_t(NUTContext *nut, StreamContext *nus, ByteIOContext *bc, uint64_t val){
val *= nut->time_base_count;
val += nus->time_base - nut->time_base;
put_v(bc, val);
}
/**
* Stores a string as vb.
*/
static void put_str(ByteIOContext *bc, const char *string){
int len= strlen(string);
put_v(bc, len);
put_buffer(bc, string, len);
}
static void put_s(ByteIOContext *bc, int64_t val){
put_v(bc, 2*FFABS(val) - (val>0));
}
#ifdef TRACE
static inline void put_v_trace(ByteIOContext *bc, uint64_t v, char *file, char *func, int line){
av_log(NULL, AV_LOG_DEBUG, "put_v %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
put_v(bc, v);
}
static inline void put_s_trace(ByteIOContext *bc, int64_t v, char *file, char *func, int line){
av_log(NULL, AV_LOG_DEBUG, "put_s %5"PRId64" / %"PRIX64" in %s %s:%d\n", v, v, file, func, line);
put_s(bc, v);
}
#define put_v(bc, v) put_v_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#define put_s(bc, v) put_s_trace(bc, v, __FILE__, __PRETTY_FUNCTION__, __LINE__)
#endif
//FIXME remove calculate_checksum
static void put_packet(NUTContext *nut, ByteIOContext *bc, ByteIOContext *dyn_bc, int calculate_checksum, uint64_t startcode){
uint8_t *dyn_buf=NULL;
int dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
int forw_ptr= dyn_size + 4*calculate_checksum;
if(forw_ptr > 4096)
init_checksum(bc, ff_crc04C11DB7_update, 0);
put_be64(bc, startcode);
put_v(bc, forw_ptr);
if(forw_ptr > 4096)
put_le32(bc, get_checksum(bc));
if(calculate_checksum)
init_checksum(bc, ff_crc04C11DB7_update, 0);
put_buffer(bc, dyn_buf, dyn_size);
if(calculate_checksum)
put_le32(bc, get_checksum(bc));
av_free(dyn_buf);
}
static void write_mainheader(NUTContext *nut, ByteIOContext *bc){
int i, j, tmp_pts, tmp_flags, tmp_stream, tmp_mul, tmp_size, tmp_fields, tmp_head_idx;
int64_t tmp_match;
put_v(bc, 3); /* version */
put_v(bc, nut->avf->nb_streams);
put_v(bc, nut->max_distance);
put_v(bc, nut->time_base_count);
for(i=0; i<nut->time_base_count; i++){
put_v(bc, nut->time_base[i].num);
put_v(bc, nut->time_base[i].den);
}
tmp_pts=0;
tmp_mul=1;
tmp_stream=0;
tmp_match= 1-(1LL<<62);
tmp_head_idx= 0;
for(i=0; i<256;){
tmp_fields=0;
tmp_size=0;
// tmp_res=0;
if(tmp_pts != nut->frame_code[i].pts_delta) tmp_fields=1;
if(tmp_mul != nut->frame_code[i].size_mul ) tmp_fields=2;
if(tmp_stream != nut->frame_code[i].stream_id) tmp_fields=3;
if(tmp_size != nut->frame_code[i].size_lsb ) tmp_fields=4;
// if(tmp_res != nut->frame_code[i].res ) tmp_fields=5;
if(tmp_head_idx!=nut->frame_code[i].header_idx)tmp_fields=8;
tmp_pts = nut->frame_code[i].pts_delta;
tmp_flags = nut->frame_code[i].flags;
tmp_stream= nut->frame_code[i].stream_id;
tmp_mul = nut->frame_code[i].size_mul;
tmp_size = nut->frame_code[i].size_lsb;
// tmp_res = nut->frame_code[i].res;
tmp_head_idx= nut->frame_code[i].header_idx;
for(j=0; i<256; j++,i++){
if(i == 'N'){
j--;
continue;
}
if(nut->frame_code[i].pts_delta != tmp_pts ) break;
if(nut->frame_code[i].flags != tmp_flags ) break;
if(nut->frame_code[i].stream_id != tmp_stream) break;
if(nut->frame_code[i].size_mul != tmp_mul ) break;
if(nut->frame_code[i].size_lsb != tmp_size+j) break;
// if(nut->frame_code[i].res != tmp_res ) break;
if(nut->frame_code[i].header_idx!= tmp_head_idx) break;
}
if(j != tmp_mul - tmp_size) tmp_fields=6;
put_v(bc, tmp_flags);
put_v(bc, tmp_fields);
if(tmp_fields>0) put_s(bc, tmp_pts);
if(tmp_fields>1) put_v(bc, tmp_mul);
if(tmp_fields>2) put_v(bc, tmp_stream);
if(tmp_fields>3) put_v(bc, tmp_size);
if(tmp_fields>4) put_v(bc, 0 /*tmp_res*/);
if(tmp_fields>5) put_v(bc, j);
if(tmp_fields>6) put_v(bc, tmp_match);
if(tmp_fields>7) put_v(bc, tmp_head_idx);
}
put_v(bc, nut->header_count-1);
for(i=1; i<nut->header_count; i++){
put_v(bc, nut->header_len[i]);
put_buffer(bc, nut->header[i], nut->header_len[i]);
}
}
static int write_streamheader(NUTContext *nut, ByteIOContext *bc, AVCodecContext *codec, int i){
put_v(bc, i);
switch(codec->codec_type){
case CODEC_TYPE_VIDEO: put_v(bc, 0); break;
case CODEC_TYPE_AUDIO: put_v(bc, 1); break;
// case CODEC_TYPE_TEXT : put_v(bc, 2); break;
default : put_v(bc, 3); break;
}
put_v(bc, 4);
if (codec->codec_tag){
put_le32(bc, codec->codec_tag);
}else
return -1;
put_v(bc, nut->stream[i].time_base - nut->time_base);
put_v(bc, nut->stream[i].msb_pts_shift);
put_v(bc, nut->stream[i].max_pts_distance);
put_v(bc, codec->has_b_frames);
put_byte(bc, 0); /* flags: 0x1 - fixed_fps, 0x2 - index_present */
put_v(bc, codec->extradata_size);
put_buffer(bc, codec->extradata, codec->extradata_size);
switch(codec->codec_type){
case CODEC_TYPE_AUDIO:
put_v(bc, codec->sample_rate);
put_v(bc, 1);
put_v(bc, codec->channels);
break;
case CODEC_TYPE_VIDEO:
put_v(bc, codec->width);
put_v(bc, codec->height);
if(codec->sample_aspect_ratio.num<=0 || codec->sample_aspect_ratio.den<=0){
put_v(bc, 0);
put_v(bc, 0);
}else{
put_v(bc, codec->sample_aspect_ratio.num);
put_v(bc, codec->sample_aspect_ratio.den);
}
put_v(bc, 0); /* csp type -- unknown */
break;
default:
break;
}
return 0;
}
static int add_info(ByteIOContext *bc, const char *type, const char *value){
put_str(bc, type);
put_s(bc, -1);
put_str(bc, value);
return 1;
}
static int write_globalinfo(NUTContext *nut, ByteIOContext *bc){
AVFormatContext *s= nut->avf;
ByteIOContext *dyn_bc;
uint8_t *dyn_buf=NULL;
int count=0, dyn_size;
int ret = url_open_dyn_buf(&dyn_bc);
if(ret < 0)
return ret;
if(s->title [0]) count+= add_info(dyn_bc, "Title" , s->title);
if(s->author [0]) count+= add_info(dyn_bc, "Author" , s->author);
if(s->copyright[0]) count+= add_info(dyn_bc, "Copyright", s->copyright);
if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
count+= add_info(dyn_bc, "Encoder" , LIBAVFORMAT_IDENT);
put_v(bc, 0); //stream_if_plus1
put_v(bc, 0); //chapter_id
put_v(bc, 0); //timestamp_start
put_v(bc, 0); //length
put_v(bc, count);
dyn_size= url_close_dyn_buf(dyn_bc, &dyn_buf);
put_buffer(bc, dyn_buf, dyn_size);
av_free(dyn_buf);
return 0;
}
static int write_headers(NUTContext *nut, ByteIOContext *bc){
ByteIOContext *dyn_bc;
int i, ret;
ret = url_open_dyn_buf(&dyn_bc);
if(ret < 0)
return ret;
write_mainheader(nut, dyn_bc);
put_packet(nut, bc, dyn_bc, 1, MAIN_STARTCODE);
for (i=0; i < nut->avf->nb_streams; i++){
AVCodecContext *codec = nut->avf->streams[i]->codec;
ret = url_open_dyn_buf(&dyn_bc);
if(ret < 0)
return ret;
write_streamheader(nut, dyn_bc, codec, i);
put_packet(nut, bc, dyn_bc, 1, STREAM_STARTCODE);
}
ret = url_open_dyn_buf(&dyn_bc);
if(ret < 0)
return ret;
write_globalinfo(nut, dyn_bc);
put_packet(nut, bc, dyn_bc, 1, INFO_STARTCODE);
nut->last_syncpoint_pos= INT_MIN;
nut->header_count++;
return 0;
}
static int write_header(AVFormatContext *s){
NUTContext *nut = s->priv_data;
ByteIOContext *bc = s->pb;
int i, j;
nut->avf= s;
nut->stream = av_mallocz(sizeof(StreamContext)*s->nb_streams);
nut->time_base= av_mallocz(sizeof(AVRational )*s->nb_streams);
for(i=0; i<s->nb_streams; i++){
AVStream *st= s->streams[i];
int ssize;
AVRational time_base;
ff_parse_specific_params(st->codec, &time_base.den, &ssize, &time_base.num);
av_set_pts_info(st, 64, time_base.num, time_base.den);
for(j=0; j<nut->time_base_count; j++){
if(!memcmp(&time_base, &nut->time_base[j], sizeof(AVRational))){
break;
}
}
nut->time_base[j]= time_base;
nut->stream[i].time_base= &nut->time_base[j];
if(j==nut->time_base_count)
nut->time_base_count++;
if(av_q2d(time_base) >= 0.001)
nut->stream[i].msb_pts_shift = 7;
else
nut->stream[i].msb_pts_shift = 14;
nut->stream[i].max_pts_distance= FFMAX(1/av_q2d(time_base), 1);
}
nut->max_distance = MAX_DISTANCE;
build_elision_headers(s);
build_frame_code(s);
assert(nut->frame_code['N'].flags == FLAG_INVALID);
put_buffer(bc, ID_STRING, strlen(ID_STRING));
put_byte(bc, 0);
write_headers(nut, bc);
put_flush_packet(bc);
//FIXME index
return 0;
}
static int get_needed_flags(NUTContext *nut, StreamContext *nus, FrameCode *fc, AVPacket *pkt){
int flags= 0;
if(pkt->flags & PKT_FLAG_KEY ) flags |= FLAG_KEY;
if(pkt->stream_index != fc->stream_id ) flags |= FLAG_STREAM_ID;
if(pkt->size / fc->size_mul ) flags |= FLAG_SIZE_MSB;
if(pkt->pts - nus->last_pts != fc->pts_delta) flags |= FLAG_CODED_PTS;
if(pkt->size > 2*nut->max_distance ) flags |= FLAG_CHECKSUM;
if(FFABS(pkt->pts - nus->last_pts)
> nus->max_pts_distance) flags |= FLAG_CHECKSUM;
if( pkt->size < nut->header_len[fc->header_idx]
|| (pkt->size > 4096 && fc->header_idx)
|| memcmp(pkt->data, nut->header[fc->header_idx], nut->header_len[fc->header_idx]))
flags |= FLAG_HEADER_IDX;
return flags | (fc->flags & FLAG_CODED);
}
static int find_best_header_idx(NUTContext *nut, AVPacket *pkt){
int i;
int best_i = 0;
int best_len= 0;
if(pkt->size > 4096)
return 0;
for(i=1; i<nut->header_count; i++){
if( pkt->size >= nut->header_len[i]
&& nut->header_len[i] > best_len
&& !memcmp(pkt->data, nut->header[i], nut->header_len[i])){
best_i= i;
best_len= nut->header_len[i];
}
}
return best_i;
}
static int write_packet(AVFormatContext *s, AVPacket *pkt){
NUTContext *nut = s->priv_data;
StreamContext *nus= &nut->stream[pkt->stream_index];
ByteIOContext *bc = s->pb, *dyn_bc;
FrameCode *fc;
int64_t coded_pts;
int best_length, frame_code, flags, needed_flags, i, header_idx, best_header_idx;
int key_frame = !!(pkt->flags & PKT_FLAG_KEY);
int store_sp=0;
int ret;
if(1LL<<(20+3*nut->header_count) <= url_ftell(bc))
write_headers(nut, bc);
if(key_frame && !(nus->last_flags & FLAG_KEY))
store_sp= 1;
if(pkt->size + 30/*FIXME check*/ + url_ftell(bc) >= nut->last_syncpoint_pos + nut->max_distance)
store_sp= 1;
//FIXME: Ensure store_sp is 1 in the first place.
if(store_sp){
syncpoint_t *sp, dummy= {.pos= INT64_MAX};
ff_nut_reset_ts(nut, *nus->time_base, pkt->dts);
for(i=0; i<s->nb_streams; i++){
AVStream *st= s->streams[i];
int64_t dts_tb = av_rescale_rnd(pkt->dts,
nus->time_base->num * (int64_t)nut->stream[i].time_base->den,
nus->time_base->den * (int64_t)nut->stream[i].time_base->num,
AV_ROUND_DOWN);
int index= av_index_search_timestamp(st, dts_tb, AVSEEK_FLAG_BACKWARD);
if(index>=0) dummy.pos= FFMIN(dummy.pos, st->index_entries[index].pos);
}
if(dummy.pos == INT64_MAX)
dummy.pos= 0;
sp= av_tree_find(nut->syncpoints, &dummy, ff_nut_sp_pos_cmp, NULL);
nut->last_syncpoint_pos= url_ftell(bc);
ret = url_open_dyn_buf(&dyn_bc);
if(ret < 0)
return ret;
put_t(nut, nus, dyn_bc, pkt->dts);
put_v(dyn_bc, sp ? (nut->last_syncpoint_pos - sp->pos)>>4 : 0);
put_packet(nut, bc, dyn_bc, 1, SYNCPOINT_STARTCODE);
ff_nut_add_sp(nut, nut->last_syncpoint_pos, 0/*unused*/, pkt->dts);
}
assert(nus->last_pts != AV_NOPTS_VALUE);
coded_pts = pkt->pts & ((1<<nus->msb_pts_shift)-1);
if(ff_lsb2full(nus, coded_pts) != pkt->pts)
coded_pts= pkt->pts + (1<<nus->msb_pts_shift);
best_header_idx= find_best_header_idx(nut, pkt);
best_length=INT_MAX;
frame_code= -1;
for(i=0; i<256; i++){
int length= 0;
FrameCode *fc= &nut->frame_code[i];
int flags= fc->flags;
if(flags & FLAG_INVALID)
continue;
needed_flags= get_needed_flags(nut, nus, fc, pkt);
if(flags & FLAG_CODED){
length++;
flags = needed_flags;
}
if((flags & needed_flags) != needed_flags)
continue;
if((flags ^ needed_flags) & FLAG_KEY)
continue;
if(flags & FLAG_STREAM_ID)
length+= get_length(pkt->stream_index);
if(pkt->size % fc->size_mul != fc->size_lsb)
continue;
if(flags & FLAG_SIZE_MSB)
length += get_length(pkt->size / fc->size_mul);
if(flags & FLAG_CHECKSUM)
length+=4;
if(flags & FLAG_CODED_PTS)
length += get_length(coded_pts);
if( (flags & FLAG_CODED)
&& nut->header_len[best_header_idx] > nut->header_len[fc->header_idx]+1){
flags |= FLAG_HEADER_IDX;
}
if(flags & FLAG_HEADER_IDX){
length += 1 - nut->header_len[best_header_idx];
}else{
length -= nut->header_len[fc->header_idx];
}
length*=4;
length+= !(flags & FLAG_CODED_PTS);
length+= !(flags & FLAG_CHECKSUM);
if(length < best_length){
best_length= length;
frame_code=i;
}
}
assert(frame_code != -1);
fc= &nut->frame_code[frame_code];
flags= fc->flags;
needed_flags= get_needed_flags(nut, nus, fc, pkt);
header_idx= fc->header_idx;
init_checksum(bc, ff_crc04C11DB7_update, 0);
put_byte(bc, frame_code);
if(flags & FLAG_CODED){
put_v(bc, (flags^needed_flags) & ~(FLAG_CODED));
flags = needed_flags;
}
if(flags & FLAG_STREAM_ID) put_v(bc, pkt->stream_index);
if(flags & FLAG_CODED_PTS) put_v(bc, coded_pts);
if(flags & FLAG_SIZE_MSB) put_v(bc, pkt->size / fc->size_mul);
if(flags & FLAG_HEADER_IDX) put_v(bc, header_idx= best_header_idx);
if(flags & FLAG_CHECKSUM) put_le32(bc, get_checksum(bc));
else get_checksum(bc);
put_buffer(bc, pkt->data + nut->header_len[header_idx], pkt->size - nut->header_len[header_idx]);
nus->last_flags= flags;
//FIXME just store one per syncpoint
if(flags & FLAG_KEY)
av_add_index_entry(
s->streams[pkt->stream_index],
nut->last_syncpoint_pos,
pkt->pts,
0,
0,
AVINDEX_KEYFRAME);
return 0;
}
static int write_trailer(AVFormatContext *s){
NUTContext *nut= s->priv_data;
ByteIOContext *bc= s->pb;
while(nut->header_count<3)
write_headers(nut, bc);
put_flush_packet(bc);
return 0;
}
AVOutputFormat nut_muxer = {
"nut",
"nut format",
"video/x-nut",
"nut",
sizeof(NUTContext),
#ifdef CONFIG_LIBVORBIS
CODEC_ID_VORBIS,
#elif defined(CONFIG_LIBMP3LAME)
CODEC_ID_MP3,
#else
CODEC_ID_MP2, /* AC3 needs liba52 decoder */
#endif
CODEC_ID_MPEG4,
write_header,
write_packet,
write_trailer,
.flags = AVFMT_GLOBALHEADER,
.codec_tag= (const AVCodecTag*[]){codec_bmp_tags, codec_wav_tags, 0},
};
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