diff options
Diffstat (limited to 'libavcodec/bitstream_filter.c')
| -rw-r--r-- | libavcodec/bitstream_filter.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/libavcodec/bitstream_filter.c b/libavcodec/bitstream_filter.c index 8f878cd0da..ef2d7414a6 100644 --- a/libavcodec/bitstream_filter.c +++ b/libavcodec/bitstream_filter.c @@ -19,6 +19,7 @@ */ #include "avcodec.h" +#include "mpegaudio.h" AVBitStreamFilter *first_bitstream_filter= NULL; @@ -124,6 +125,112 @@ static int noise(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const ch return 1; } +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; + int mode_extension; + + if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){ + av_log(avctx, AV_LOG_ERROR, "not standards compliant\n"); + return -1; + } + + header = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]; + mode_extension= (header>>4)&3; + + if(ff_mpa_check_header(header) < 0 || (header&0x70000) != 0x30000){ + *poutbuf= (uint8_t *) buf; + *poutbuf_size= buf_size; + + av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header); + return 0; + } + + *poutbuf_size= buf_size - 4; + *poutbuf= av_malloc(buf_size - 4 + FF_INPUT_BUFFER_PADDING_SIZE); + memcpy(*poutbuf, buf + 4, buf_size - 4 + 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 = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]; + if(ff_mpa_check_header(header) >= 0){ + *poutbuf= (uint8_t *) buf; + *poutbuf_size= buf_size; + + return 0; + } + + header= 0xFFE00000 | ((4-3)<<17) | (1<<16); //FIXME simplify + + lsf = sample_rate < (24000+32000)/2; + mpeg25 = sample_rate < (12000+16000)/2; + header |= (!mpeg25)<<20; + header |= (!lsf )<<19; + if(sample_rate<<(lsf+mpeg25) < (44100+32000)/2) + sample_rate_index |= 2; + else if(sample_rate<<(lsf+mpeg25) > (44100+48000)/2) + sample_rate_index |= 1; + + header |= sample_rate_index<<10; + 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(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 |= (avctx->channels==1 ? MPA_MONO : MPA_JSTEREO)<<6; + + *poutbuf_size= buf_size + 4; + *poutbuf= av_malloc(buf_size + 4 + FF_INPUT_BUFFER_PADDING_SIZE); + memcpy(*poutbuf + 4, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE); + + if(avctx->channels==2){ + if(lsf){ + FFSWAP(int, (*poutbuf)[5], (*poutbuf)[6]); + header |= ((*poutbuf)[5] & 0xC0)>>2; + }else{ + header |= (*poutbuf)[5] & 0x30; + } + } + + (*poutbuf)[0]= header>>24; + (*poutbuf)[1]= header>>16; + (*poutbuf)[2]= header>> 8; + (*poutbuf)[3]= header ; + + return 1; +} + AVBitStreamFilter dump_extradata_bsf={ "dump_extra", 0, @@ -141,3 +248,15 @@ AVBitStreamFilter noise_bsf={ sizeof(int), noise, }; + +AVBitStreamFilter mp3_header_compress_bsf={ + "mp3comp", + 0, + mp3_header_compress, +}; + +AVBitStreamFilter mp3_header_decompress_bsf={ + "mp3decomp", + 0, + mp3_header_decompress, +}; |