yading@10: /*
yading@10:  * MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration bitstream filter
yading@10:  * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "aacadtsdec.h"
yading@10: #include "put_bits.h"
yading@10: #include "get_bits.h"
yading@10: #include "mpeg4audio.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: typedef struct AACBSFContext {
yading@10:     int first_frame_done;
yading@10: } AACBSFContext;
yading@10: 
yading@10: /**
yading@10:  * This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
yading@10:  * ADTS header and removes the ADTS header.
yading@10:  */
yading@10: static int aac_adtstoasc_filter(AVBitStreamFilterContext *bsfc,
yading@10:                                 AVCodecContext *avctx, const char *args,
yading@10:                                 uint8_t  **poutbuf, int *poutbuf_size,
yading@10:                                 const uint8_t *buf, int      buf_size,
yading@10:                                 int keyframe)
yading@10: {
yading@10:     GetBitContext gb;
yading@10:     PutBitContext pb;
yading@10:     AACADTSHeaderInfo hdr;
yading@10: 
yading@10:     AACBSFContext *ctx = bsfc->priv_data;
yading@10: 
yading@10:     init_get_bits(&gb, buf, AAC_ADTS_HEADER_SIZE*8);
yading@10: 
yading@10:     *poutbuf = (uint8_t*) buf;
yading@10:     *poutbuf_size = buf_size;
yading@10: 
yading@10:     if (avctx->extradata)
yading@10:         if (show_bits(&gb, 12) != 0xfff)
yading@10:             return 0;
yading@10: 
yading@10:     if (avpriv_aac_parse_header(&gb, &hdr) < 0) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Error parsing ADTS frame header!\n");
yading@10:         return -1;
yading@10:     }
yading@10: 
yading@10:     if (!hdr.crc_absent && hdr.num_aac_frames > 1) {
yading@10:         avpriv_report_missing_feature(avctx,
yading@10:                                       "Multiple RDBs per frame with CRC");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     buf      += AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
yading@10:     buf_size -= AAC_ADTS_HEADER_SIZE + 2*!hdr.crc_absent;
yading@10: 
yading@10:     if (!ctx->first_frame_done) {
yading@10:         int            pce_size = 0;
yading@10:         uint8_t        pce_data[MAX_PCE_SIZE];
yading@10:         if (!hdr.chan_config) {
yading@10:             init_get_bits(&gb, buf, buf_size * 8);
yading@10:             if (get_bits(&gb, 3) != 5) {
yading@10:                 avpriv_report_missing_feature(avctx,
yading@10:                                               "PCE-based channel configuration "
yading@10:                                               "without PCE as first syntax "
yading@10:                                               "element");
yading@10:                 return AVERROR_PATCHWELCOME;
yading@10:             }
yading@10:             init_put_bits(&pb, pce_data, MAX_PCE_SIZE);
yading@10:             pce_size = avpriv_copy_pce_data(&pb, &gb)/8;
yading@10:             flush_put_bits(&pb);
yading@10:             buf_size -= get_bits_count(&gb)/8;
yading@10:             buf      += get_bits_count(&gb)/8;
yading@10:         }
yading@10:         avctx->extradata_size = 2 + pce_size;
yading@10:         avctx->extradata = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
yading@10: 
yading@10:         init_put_bits(&pb, avctx->extradata, avctx->extradata_size);
yading@10:         put_bits(&pb, 5, hdr.object_type);
yading@10:         put_bits(&pb, 4, hdr.sampling_index);
yading@10:         put_bits(&pb, 4, hdr.chan_config);
yading@10:         put_bits(&pb, 1, 0); //frame length - 1024 samples
yading@10:         put_bits(&pb, 1, 0); //does not depend on core coder
yading@10:         put_bits(&pb, 1, 0); //is not extension
yading@10:         flush_put_bits(&pb);
yading@10:         if (pce_size) {
yading@10:             memcpy(avctx->extradata + 2, pce_data, pce_size);
yading@10:         }
yading@10: 
yading@10:         ctx->first_frame_done = 1;
yading@10:     }
yading@10: 
yading@10:     *poutbuf = (uint8_t*) buf;
yading@10:     *poutbuf_size = buf_size;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVBitStreamFilter ff_aac_adtstoasc_bsf = {
yading@10:     "aac_adtstoasc",
yading@10:     sizeof(AACBSFContext),
yading@10:     aac_adtstoasc_filter,
yading@10: };