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 "internal.h"
00034 #include "gsm.h"
00035 
00036 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
00037     if (avctx->channels > 1) {
00038         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
00039                avctx->channels);
00040         return -1;
00041     }
00042 
00043     if (avctx->sample_rate != 8000) {
00044         av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
00045                avctx->sample_rate);
00046         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
00047             return -1;
00048     }
00049     if (avctx->bit_rate != 13000 /* Official */ &&
00050         avctx->bit_rate != 13200 /* Very common */ &&
00051         avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
00052         av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
00053                avctx->bit_rate);
00054         if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
00055             return -1;
00056     }
00057 
00058     avctx->priv_data = gsm_create();
00059 
00060     switch(avctx->codec_id) {
00061     case CODEC_ID_GSM:
00062         avctx->frame_size = GSM_FRAME_SIZE;
00063         avctx->block_align = GSM_BLOCK_SIZE;
00064         break;
00065     case CODEC_ID_GSM_MS: {
00066         int one = 1;
00067         gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
00068         avctx->frame_size = 2*GSM_FRAME_SIZE;
00069         avctx->block_align = GSM_MS_BLOCK_SIZE;
00070         }
00071     }
00072 
00073     avctx->coded_frame= avcodec_alloc_frame();
00074     avctx->coded_frame->key_frame= 1;
00075 
00076     return 0;
00077 }
00078 
00079 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
00080     av_freep(&avctx->coded_frame);
00081     gsm_destroy(avctx->priv_data);
00082     avctx->priv_data = NULL;
00083     return 0;
00084 }
00085 
00086 static int libgsm_encode_frame(AVCodecContext *avctx,
00087                                unsigned char *frame, int buf_size, void *data) {
00088     // we need a full block
00089     if(buf_size < avctx->block_align) return 0;
00090 
00091     switch(avctx->codec_id) {
00092     case CODEC_ID_GSM:
00093         gsm_encode(avctx->priv_data,data,frame);
00094         break;
00095     case CODEC_ID_GSM_MS:
00096         gsm_encode(avctx->priv_data,data,frame);
00097         gsm_encode(avctx->priv_data,((short*)data)+GSM_FRAME_SIZE,frame+32);
00098     }
00099     return avctx->block_align;
00100 }
00101 
00102 
00103 AVCodec ff_libgsm_encoder = {
00104     .name           = "libgsm",
00105     .type           = AVMEDIA_TYPE_AUDIO,
00106     .id             = CODEC_ID_GSM,
00107     .init           = libgsm_encode_init,
00108     .encode         = libgsm_encode_frame,
00109     .close          = libgsm_encode_close,
00110     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00111     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
00112 };
00113 
00114 AVCodec ff_libgsm_ms_encoder = {
00115     .name           = "libgsm_ms",
00116     .type           = AVMEDIA_TYPE_AUDIO,
00117     .id             = CODEC_ID_GSM_MS,
00118     .init           = libgsm_encode_init,
00119     .encode         = libgsm_encode_frame,
00120     .close          = libgsm_encode_close,
00121     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00122     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
00123 };
00124 
00125 typedef struct LibGSMDecodeContext {
00126     AVFrame frame;
00127     struct gsm_state *state;
00128 } LibGSMDecodeContext;
00129 
00130 static av_cold int libgsm_decode_init(AVCodecContext *avctx) {
00131     LibGSMDecodeContext *s = avctx->priv_data;
00132 
00133     if (avctx->channels > 1) {
00134         av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
00135                avctx->channels);
00136         return -1;
00137     }
00138 
00139     if (!avctx->channels)
00140         avctx->channels = 1;
00141 
00142     if (!avctx->sample_rate)
00143         avctx->sample_rate = 8000;
00144 
00145     avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00146 
00147     s->state = gsm_create();
00148 
00149     switch(avctx->codec_id) {
00150     case CODEC_ID_GSM:
00151         avctx->frame_size  = GSM_FRAME_SIZE;
00152         avctx->block_align = GSM_BLOCK_SIZE;
00153         break;
00154     case CODEC_ID_GSM_MS: {
00155         int one = 1;
00156         gsm_option(s->state, GSM_OPT_WAV49, &one);
00157         avctx->frame_size  = 2 * GSM_FRAME_SIZE;
00158         avctx->block_align = GSM_MS_BLOCK_SIZE;
00159         }
00160     }
00161 
00162     avcodec_get_frame_defaults(&s->frame);
00163     avctx->coded_frame = &s->frame;
00164 
00165     return 0;
00166 }
00167 
00168 static av_cold int libgsm_decode_close(AVCodecContext *avctx) {
00169     LibGSMDecodeContext *s = avctx->priv_data;
00170 
00171     gsm_destroy(s->state);
00172     s->state = NULL;
00173     return 0;
00174 }
00175 
00176 static int libgsm_decode_frame(AVCodecContext *avctx, void *data,
00177                                int *got_frame_ptr, AVPacket *avpkt)
00178 {
00179     int i, ret;
00180     LibGSMDecodeContext *s = avctx->priv_data;
00181     uint8_t *buf = avpkt->data;
00182     int buf_size = avpkt->size;
00183     int16_t *samples;
00184 
00185     if (buf_size < avctx->block_align) {
00186         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
00187         return AVERROR_INVALIDDATA;
00188     }
00189 
00190     /* get output buffer */
00191     s->frame.nb_samples = avctx->frame_size;
00192     if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
00193         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00194         return ret;
00195     }
00196     samples = (int16_t *)s->frame.data[0];
00197 
00198     for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) {
00199         if ((ret = gsm_decode(s->state, buf, samples)) < 0)
00200             return -1;
00201         buf     += GSM_BLOCK_SIZE;
00202         samples += GSM_FRAME_SIZE;
00203     }
00204 
00205     *got_frame_ptr   = 1;
00206     *(AVFrame *)data = s->frame;
00207 
00208     return avctx->block_align;
00209 }
00210 
00211 static void libgsm_flush(AVCodecContext *avctx) {
00212     LibGSMDecodeContext *s = avctx->priv_data;
00213     int one = 1;
00214 
00215     gsm_destroy(s->state);
00216     s->state = gsm_create();
00217     if (avctx->codec_id == CODEC_ID_GSM_MS)
00218         gsm_option(s->state, GSM_OPT_WAV49, &one);
00219 }
00220 
00221 AVCodec ff_libgsm_decoder = {
00222     .name           = "libgsm",
00223     .type           = AVMEDIA_TYPE_AUDIO,
00224     .id             = CODEC_ID_GSM,
00225     .priv_data_size = sizeof(LibGSMDecodeContext),
00226     .init           = libgsm_decode_init,
00227     .close          = libgsm_decode_close,
00228     .decode         = libgsm_decode_frame,
00229     .flush          = libgsm_flush,
00230     .capabilities   = CODEC_CAP_DR1,
00231     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
00232 };
00233 
00234 AVCodec ff_libgsm_ms_decoder = {
00235     .name           = "libgsm_ms",
00236     .type           = AVMEDIA_TYPE_AUDIO,
00237     .id             = CODEC_ID_GSM_MS,
00238     .priv_data_size = sizeof(LibGSMDecodeContext),
00239     .init           = libgsm_decode_init,
00240     .close          = libgsm_decode_close,
00241     .decode         = libgsm_decode_frame,
00242     .flush          = libgsm_flush,
00243     .capabilities   = CODEC_CAP_DR1,
00244     .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
00245 };