libavcodec/libgsm.c
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00001 /*
00002  * Interface to libgsm for gsm encoding/decoding
00003  * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
00004  * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
00005  *
00006  * This file is part of Libav.
00007  *
00008  * Libav is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * Libav is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with Libav; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00028 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
00029 
00030 #include <gsm/gsm.h>
00031 
00032 #include "avcodec.h"
00033 #include "gsm.h"
00034 
00035 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
00036     if (avctx->channels > 1) {
00037         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
00038                avctx->channels);
00039         return -1;
00040     }
00041 
00042     if (avctx->sample_rate != 8000) {
00043         av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
00044                avctx->sample_rate);
00045         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
00046             return -1;
00047     }
00048     if (avctx->bit_rate != 13000 /* Official */ &&
00049         avctx->bit_rate != 13200 /* Very common */ &&
00050         avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
00051         av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
00052                avctx->bit_rate);
00053         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
00054             return -1;
00055     }
00056 
00057     avctx->priv_data = gsm_create();
00058 
00059     switch(avctx->codec_id) {
00060     case CODEC_ID_GSM:
00061         avctx->frame_size = GSM_FRAME_SIZE;
00062         avctx->block_align = GSM_BLOCK_SIZE;
00063         break;
00064     case CODEC_ID_GSM_MS: {
00065         int one = 1;
00066         gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
00067         avctx->frame_size = 2*GSM_FRAME_SIZE;
00068         avctx->block_align = GSM_MS_BLOCK_SIZE;
00069         }
00070     }
00071 
00072     avctx->coded_frame= avcodec_alloc_frame();
00073     avctx->coded_frame->key_frame= 1;
00074 
00075     return 0;
00076 }
00077 
00078 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
00079     av_freep(&avctx->coded_frame);
00080     gsm_destroy(avctx->priv_data);
00081     avctx->priv_data = NULL;
00082     return 0;
00083 }
00084 
00085 static int libgsm_encode_frame(AVCodecContext *avctx,
00086                                unsigned char *frame, int buf_size, void *data) {
00087     // we need a full block
00088     if(buf_size < avctx->block_align) return 0;
00089 
00090     switch(avctx->codec_id) {
00091     case CODEC_ID_GSM:
00092         gsm_encode(avctx->priv_data,data,frame);
00093         break;
00094     case CODEC_ID_GSM_MS:
00095         gsm_encode(avctx->priv_data,data,frame);
00096         gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32);
00097     }
00098     return avctx->block_align;
00099 }
00100 
00101 
00102 AVCodec ff_libgsm_encoder = {
00103     .name           = "libgsm",
00104     .type           = AVMEDIA_TYPE_AUDIO,
00105     .id             = CODEC_ID_GSM,
00106     .init           = libgsm_encode_init,
00107     .encode         = libgsm_encode_frame,
00108     .close          = libgsm_encode_close,
00109     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00110     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
00111 };
00112 
00113 AVCodec ff_libgsm_ms_encoder = {
00114     .name           = "libgsm_ms",
00115     .type           = AVMEDIA_TYPE_AUDIO,
00116     .id             = CODEC_ID_GSM_MS,
00117     .init           = libgsm_encode_init,
00118     .encode         = libgsm_encode_frame,
00119     .close          = libgsm_encode_close,
00120     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00121     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
00122 };
00123 
00124 typedef struct LibGSMDecodeContext {
00125     AVFrame frame;
00126     struct gsm_state *state;
00127 } LibGSMDecodeContext;
00128 
00129 static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
00130     LibGSMDecodeContext *s = avctx->priv_data;
00131 
00132     if (avctx->channels > 1) {
00133         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
00134                avctx->channels);
00135         return -1;
00136     }
00137 
00138     if (!avctx->channels)
00139         avctx->channels = 1;
00140 
00141     if (!avctx->sample_rate)
00142         avctx->sample_rate = 8000;
00143 
00144     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00145 
00146     s->state = gsm_create();
00147 
00148     switch(avctx->codec_id) {
00149     case CODEC_ID_GSM:
00150         avctx->frame_size  = GSM_FRAME_SIZE;
00151         avctx->block_align = GSM_BLOCK_SIZE;
00152         break;
00153     case CODEC_ID_GSM_MS: {
00154         int one = 1;
00155         gsm_option(s->state, GSM_OPT_WAV49, &one);
00156         avctx->frame_size  = 2 * GSM_FRAME_SIZE;
00157         avctx->block_align = GSM_MS_BLOCK_SIZE;
00158         }
00159     }
00160 
00161     avcodec_get_frame_defaults(&s->frame);
00162     avctx->coded_frame = &s->frame;
00163 
00164     return 0;
00165 }
00166 
00167 static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
00168     LibGSMDecodeContext *s = avctx->priv_data;
00169 
00170     gsm_destroy(s->state);
00171     s->state = NULL;
00172     return 0;
00173 }
00174 
00175 static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
00176                                int *got_frame_ptr, AVPacket *avpkt)
00177 {
00178     int i, ret;
00179     LibGSMDecodeContext *s = avctx->priv_data;
00180     uint8_t *buf = avpkt->data;
00181     int buf_size = avpkt->size;
00182     int16_t *samples;
00183 
00184     if (buf_size < avctx->block_align) {
00185         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
00186         return AVERROR_INVALIDDATA;
00187     }
00188 
00189     /* get output buffer */
00190     s->frame.nb_samples = avctx->frame_size;
00191     if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
00192         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00193         return ret;
00194     }
00195     samples = (int16_t *)s->frame.data[0];
00196 
00197     for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
00198         if ((ret = gsm_decode(s->state, buf, samples)) < 0)
00199             return -1;
00200         buf     += GSM_BLOCK_SIZE;
00201         samples += GSM_FRAME_SIZE;
00202     }
00203 
00204     *got_frame_ptr   = 1;
00205     *(AVFrame *)data = s->frame;
00206 
00207     return avctx->block_align;
00208 }
00209 
00210 static void libgsm_flush(AVCodecContext *avctx) {
00211     LibGSMDecodeContext *s = avctx->priv_data;
00212     int one = 1;
00213 
00214     gsm_destroy(s->state);
00215     s->state = gsm_create();
00216     if (avctx->codec_id == CODEC_ID_GSM_MS)
00217         gsm_option(s->state, GSM_OPT_WAV49, &one);
00218 }
00219 
00220 AVCodec ff_libgsm_decoder = {
00221     .name           = "libgsm",
00222     .type           = AVMEDIA_TYPE_AUDIO,
00223     .id             = CODEC_ID_GSM,
00224     .priv_data_size = sizeof(LibGSMDecodeContext),
00225     .init           = libgsm_decode_init,
00226     .close          = libgsm_decode_close,
00227     .decode         = libgsm_decode_frame,
00228     .flush          = libgsm_flush,
00229     .capabilities   = CODEC_CAP_DR1,
00230     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
00231 };
00232 
00233 AVCodec ff_libgsm_ms_decoder = {
00234     .name           = "libgsm_ms",
00235     .type           = AVMEDIA_TYPE_AUDIO,
00236     .id             = CODEC_ID_GSM_MS,
00237     .priv_data_size = sizeof(LibGSMDecodeContext),
00238     .init           = libgsm_decode_init,
00239     .close          = libgsm_decode_close,
00240     .decode         = libgsm_decode_frame,
00241     .flush          = libgsm_flush,
00242     .capabilities   = CODEC_CAP_DR1,
00243     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
00244 };