/* * Interface to libgsm for gsm encoding/decoding * Copyright (c) 2005 Alban Bedel <albeu@free.fr> * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be> * * 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 */ /** * @file libavcodec/libgsm.c * Interface to libgsm for gsm encoding/decoding */ // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html #include "avcodec.h" #include <gsm/gsm.h> // gsm.h misses some essential constants #define GSM_BLOCK_SIZE 33 #define GSM_MS_BLOCK_SIZE 65 #define GSM_FRAME_SIZE 160 static av_cold int libgsm_init(AVCodecContext *avctx) { if (avctx->channels > 1) { av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n", avctx->channels); return -1; } if(avctx->codec->decode){ if(!avctx->channels) avctx->channels= 1; if(!avctx->sample_rate) avctx->sample_rate= 8000; avctx->sample_fmt = SAMPLE_FMT_S16; }else{ if (avctx->sample_rate != 8000) { av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n", avctx->sample_rate); if(avctx->strict_std_compliance > FF_COMPLIANCE_INOFFICIAL) return -1; } if (avctx->bit_rate != 13000 /* Official */ && avctx->bit_rate != 13200 /* Very common */ && avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) { av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n", avctx->bit_rate); if(avctx->strict_std_compliance > FF_COMPLIANCE_INOFFICIAL) return -1; } } avctx->priv_data = gsm_create(); switch(avctx->codec_id) { case CODEC_ID_GSM: avctx->frame_size = GSM_FRAME_SIZE; avctx->block_align = GSM_BLOCK_SIZE; break; case CODEC_ID_GSM_MS: { int one = 1; gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one); avctx->frame_size = 2*GSM_FRAME_SIZE; avctx->block_align = GSM_MS_BLOCK_SIZE; } } avctx->coded_frame= avcodec_alloc_frame(); avctx->coded_frame->key_frame= 1; return 0; } static av_cold int libgsm_close(AVCodecContext *avctx) { av_freep(&avctx->coded_frame); gsm_destroy(avctx->priv_data); avctx->priv_data = NULL; return 0; } static int libgsm_encode_frame(AVCodecContext *avctx, unsigned char *frame, int buf_size, void *data) { // we need a full block if(buf_size < avctx->block_align) return 0; switch(avctx->codec_id) { case CODEC_ID_GSM: gsm_encode(avctx->priv_data,data,frame); break; case CODEC_ID_GSM_MS: gsm_encode(avctx->priv_data,data,frame); gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32); } return avctx->block_align; } AVCodec libgsm_encoder = { "libgsm", CODEC_TYPE_AUDIO, CODEC_ID_GSM, 0, libgsm_init, libgsm_encode_frame, libgsm_close, .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE}, .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), }; AVCodec libgsm_ms_encoder = { "libgsm_ms", CODEC_TYPE_AUDIO, CODEC_ID_GSM_MS, 0, libgsm_init, libgsm_encode_frame, libgsm_close, .sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE}, .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), }; static int libgsm_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; *data_size = 0; /* In case of error */ if(buf_size < avctx->block_align) return -1; switch(avctx->codec_id) { case CODEC_ID_GSM: if(gsm_decode(avctx->priv_data,buf,data)) return -1; *data_size = GSM_FRAME_SIZE*sizeof(int16_t); break; case CODEC_ID_GSM_MS: if(gsm_decode(avctx->priv_data,buf,data) || gsm_decode(avctx->priv_data,buf+33,((int16_t*)data)+GSM_FRAME_SIZE)) return -1; *data_size = GSM_FRAME_SIZE*sizeof(int16_t)*2; } return avctx->block_align; } AVCodec libgsm_decoder = { "libgsm", CODEC_TYPE_AUDIO, CODEC_ID_GSM, 0, libgsm_init, NULL, libgsm_close, libgsm_decode_frame, .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), }; AVCodec libgsm_ms_decoder = { "libgsm_ms", CODEC_TYPE_AUDIO, CODEC_ID_GSM_MS, 0, libgsm_init, NULL, libgsm_close, libgsm_decode_frame, .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), };