1/* 2 * Interface to libgsm for GSM decoding 3 * Copyright (c) 2005 Alban Bedel <albeu@free.fr> 4 * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be> 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23/** 24 * @file 25 * Interface to libgsm for GSM decoding 26 */ 27 28// The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html 29 30#include "config.h" 31#include "config_components.h" 32#if HAVE_GSM_H 33#include <gsm.h> 34#else 35#include <gsm/gsm.h> 36#endif 37 38#include "libavutil/channel_layout.h" 39#include "libavutil/common.h" 40 41#include "avcodec.h" 42#include "codec_internal.h" 43#include "internal.h" 44#include "gsm.h" 45 46typedef struct LibGSMDecodeContext { 47 struct gsm_state *state; 48} LibGSMDecodeContext; 49 50static av_cold int libgsm_decode_init(AVCodecContext *avctx) { 51 LibGSMDecodeContext *s = avctx->priv_data; 52 53 av_channel_layout_uninit(&avctx->ch_layout); 54 avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO; 55 if (!avctx->sample_rate) 56 avctx->sample_rate = 8000; 57 avctx->sample_fmt = AV_SAMPLE_FMT_S16; 58 59 s->state = gsm_create(); 60 61 switch(avctx->codec_id) { 62 case AV_CODEC_ID_GSM: 63 avctx->frame_size = GSM_FRAME_SIZE; 64 avctx->block_align = GSM_BLOCK_SIZE; 65 break; 66 case AV_CODEC_ID_GSM_MS: { 67 int one = 1; 68 gsm_option(s->state, GSM_OPT_WAV49, &one); 69 avctx->frame_size = 2 * GSM_FRAME_SIZE; 70 avctx->block_align = GSM_MS_BLOCK_SIZE; 71 } 72 } 73 74 return 0; 75} 76 77static av_cold int libgsm_decode_close(AVCodecContext *avctx) { 78 LibGSMDecodeContext *s = avctx->priv_data; 79 80 gsm_destroy(s->state); 81 s->state = NULL; 82 return 0; 83} 84 85static int libgsm_decode_frame(AVCodecContext *avctx, AVFrame *frame, 86 int *got_frame_ptr, AVPacket *avpkt) 87{ 88 int i, ret; 89 LibGSMDecodeContext *s = avctx->priv_data; 90 uint8_t *buf = avpkt->data; 91 int buf_size = avpkt->size; 92 int16_t *samples; 93 94 if (buf_size < avctx->block_align) { 95 av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); 96 return AVERROR_INVALIDDATA; 97 } 98 99 /* get output buffer */ 100 frame->nb_samples = avctx->frame_size; 101 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) 102 return ret; 103 samples = (int16_t *)frame->data[0]; 104 105 for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) { 106 if ((ret = gsm_decode(s->state, buf, samples)) < 0) 107 return -1; 108 buf += GSM_BLOCK_SIZE; 109 samples += GSM_FRAME_SIZE; 110 } 111 112 *got_frame_ptr = 1; 113 114 return avctx->block_align; 115} 116 117static void libgsm_flush(AVCodecContext *avctx) { 118 LibGSMDecodeContext *s = avctx->priv_data; 119 int one = 1; 120 121 gsm_destroy(s->state); 122 s->state = gsm_create(); 123 if (avctx->codec_id == AV_CODEC_ID_GSM_MS) 124 gsm_option(s->state, GSM_OPT_WAV49, &one); 125} 126 127#if CONFIG_LIBGSM_DECODER 128const FFCodec ff_libgsm_decoder = { 129 .p.name = "libgsm", 130 .p.long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), 131 .p.type = AVMEDIA_TYPE_AUDIO, 132 .p.id = AV_CODEC_ID_GSM, 133 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, 134 .p.wrapper_name = "libgsm", 135 .priv_data_size = sizeof(LibGSMDecodeContext), 136 .init = libgsm_decode_init, 137 .close = libgsm_decode_close, 138 FF_CODEC_DECODE_CB(libgsm_decode_frame), 139 .flush = libgsm_flush, 140}; 141#endif 142#if CONFIG_LIBGSM_MS_DECODER 143const FFCodec ff_libgsm_ms_decoder = { 144 .p.name = "libgsm_ms", 145 .p.long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), 146 .p.type = AVMEDIA_TYPE_AUDIO, 147 .p.id = AV_CODEC_ID_GSM_MS, 148 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, 149 .p.wrapper_name = "libgsm", 150 .priv_data_size = sizeof(LibGSMDecodeContext), 151 .init = libgsm_decode_init, 152 .close = libgsm_decode_close, 153 FF_CODEC_DECODE_CB(libgsm_decode_frame), 154 .flush = libgsm_flush, 155}; 156#endif 157