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ffmpeg/libavcodec/bitstream_filter.c

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/*
* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* 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 "avcodec.h"
#include "mpegaudio.h"
AVBitStreamFilter *first_bitstream_filter= NULL;
void av_register_bitstream_filter(AVBitStreamFilter *bsf){
bsf->next = first_bitstream_filter;
first_bitstream_filter= bsf;
}
AVBitStreamFilterContext *av_bitstream_filter_init(const char *name){
AVBitStreamFilter *bsf= first_bitstream_filter;
while(bsf){
if(!strcmp(name, bsf->name)){
AVBitStreamFilterContext *bsfc= av_mallocz(sizeof(AVBitStreamFilterContext));
bsfc->filter= bsf;
bsfc->priv_data= av_mallocz(bsf->priv_data_size);
return bsfc;
}
bsf= bsf->next;
}
return NULL;
}
void av_bitstream_filter_close(AVBitStreamFilterContext *bsfc){
av_freep(&bsfc->priv_data);
av_parser_close(bsfc->parser);
av_free(bsfc);
}
int av_bitstream_filter_filter(AVBitStreamFilterContext *bsfc,
AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
*poutbuf= (uint8_t *) buf;
*poutbuf_size= buf_size;
return bsfc->filter->filter(bsfc, avctx, args, poutbuf, poutbuf_size, buf, buf_size, keyframe);
}
static int dump_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
int cmd= args ? *args : 0;
/* cast to avoid warning about discarding qualifiers */
if(avctx->extradata){
if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER) && cmd=='a')
||(keyframe && (cmd=='k' || !cmd))
||(cmd=='e')
/*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
int size= buf_size + avctx->extradata_size;
*poutbuf_size= size;
*poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
return 1;
}
}
return 0;
}
static int remove_extradata(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
int cmd= args ? *args : 0;
AVCodecParserContext *s;
if(!bsfc->parser){
bsfc->parser= av_parser_init(avctx->codec_id);
}
s= bsfc->parser;
if(s && s->parser->split){
if( (((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)) && cmd=='a')
||(!keyframe && cmd=='k')
||(cmd=='e' || !cmd)
){
int i= s->parser->split(avctx, buf, buf_size);
buf += i;
buf_size -= i;
}
}
*poutbuf= (uint8_t *) buf;
*poutbuf_size= buf_size;
return 0;
}
static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
int amount= args ? atoi(args) : 10000;
unsigned int *state= bsfc->priv_data;
int i;
*poutbuf= av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(*poutbuf, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
for(i=0; i<buf_size; i++){
(*state) += (*poutbuf)[i] + 1;
if(*state % amount == 0)
(*poutbuf)[i] = *state;
}
return 1;
}
#define MP3_MASK 0xFFFE0CCF
static int mp3_header_compress(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
uint32_t header, extraheader;
int mode_extension, header_size;
if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){
av_log(avctx, AV_LOG_ERROR, "not standards compliant\n");
return -1;
}
header = AV_RB32(buf);
mode_extension= (header>>4)&3;
if(ff_mpa_check_header(header) < 0 || (header&0x60000) != 0x20000){
output_unchanged:
*poutbuf= (uint8_t *) buf;
*poutbuf_size= buf_size;
av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header);
return 0;
}
if(avctx->extradata_size == 0){
avctx->extradata_size=15;
avctx->extradata= av_malloc(avctx->extradata_size);
strcpy(avctx->extradata, "FFCMP3 0.0");
memcpy(avctx->extradata+11, buf, 4);
}
if(avctx->extradata_size != 15){
av_log(avctx, AV_LOG_ERROR, "Extradata invalid\n");
return -1;
}
extraheader = AV_RB32(avctx->extradata+11);
if((extraheader&MP3_MASK) != (header&MP3_MASK))
goto output_unchanged;
header_size= (header&0x10000) ? 4 : 6;
*poutbuf_size= buf_size - header_size;
*poutbuf= av_malloc(buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(*poutbuf, buf + header_size, buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(avctx->channels==2){
if((header & (3<<19)) != 3<<19){
(*poutbuf)[1] &= 0x3F;
(*poutbuf)[1] |= mode_extension<<6;
FFSWAP(int, (*poutbuf)[1], (*poutbuf)[2]);
}else{
(*poutbuf)[1] &= 0x8F;
(*poutbuf)[1] |= mode_extension<<4;
}
}
return 1;
}
static int mp3_header_decompress(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size, int keyframe){
uint32_t header;
int sample_rate= avctx->sample_rate;
int sample_rate_index=0;
int lsf, mpeg25, bitrate_index, frame_size;
header = AV_RB32(buf);
if(ff_mpa_check_header(header) >= 0){
*poutbuf= (uint8_t *) buf;
*poutbuf_size= buf_size;
return 0;
}
if(avctx->extradata_size != 15 || strcmp(avctx->extradata, "FFCMP3 0.0")){
av_log(avctx, AV_LOG_ERROR, "Extradata invalid %d\n", avctx->extradata_size);
return -1;
}
header= AV_RB32(avctx->extradata+11) & MP3_MASK;
lsf = sample_rate < (24000+32000)/2;
mpeg25 = sample_rate < (12000+16000)/2;
sample_rate_index= (header>>10)&3;
sample_rate= mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off
for(bitrate_index=2; bitrate_index<30; bitrate_index++){
frame_size = mpa_bitrate_tab[lsf][2][bitrate_index>>1];
frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
if(frame_size == buf_size + 4)
break;
if(frame_size == buf_size + 6)
break;
}
if(bitrate_index == 30){
av_log(avctx, AV_LOG_ERROR, "couldnt find bitrate_index\n");
return -1;
}
header |= (bitrate_index&1)<<9;
header |= (bitrate_index>>1)<<12;
header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0
*poutbuf_size= frame_size;
*poutbuf= av_malloc(frame_size + FF_INPUT_BUFFER_PADDING_SIZE);
memcpy(*poutbuf + frame_size - buf_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(avctx->channels==2){
uint8_t *p= *poutbuf + frame_size - buf_size;
if(lsf){
FFSWAP(int, p[1], p[2]);
header |= (p[1] & 0xC0)>>2;
p[1] &= 0x3F;
}else{
header |= p[1] & 0x30;
p[1] &= 0xCF;
}
}
(*poutbuf)[0]= header>>24;
(*poutbuf)[1]= header>>16;
(*poutbuf)[2]= header>> 8;
(*poutbuf)[3]= header ;
return 1;
}
AVBitStreamFilter dump_extradata_bsf={
"dump_extra",
0,
dump_extradata,
};
AVBitStreamFilter remove_extradata_bsf={
"remove_extra",
0,
remove_extradata,
};
AVBitStreamFilter noise_bsf={
"noise",
sizeof(int),
noise,
};
AVBitStreamFilter mp3_header_compress_bsf={
"mp3comp",
0,
mp3_header_compress,
};
AVBitStreamFilter mp3_header_decompress_bsf={
"mp3decomp",
0,
mp3_header_decompress,
};
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