2 * Interface to libgsm for GSM encoding
3 * Copyright (c) 2005 Alban Bedel <albeu@free.fr>
4 * Copyright (c) 2006, 2007 Michel Bardiaux <mbardiaux@mediaxim.be>
6 * This file is part of Libav.
8 * Libav 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.
13 * Libav 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.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * Interface to libgsm for GSM encoding
28 // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html
37 #include "libavutil/common.h"
43 static av_cold int libgsm_encode_init(AVCodecContext *avctx) {
44 if (avctx->channels > 1) {
45 av_log(avctx, AV_LOG_ERROR, "Mono required for GSM, got %d channels\n",
50 if (avctx->sample_rate != 8000) {
51 av_log(avctx, AV_LOG_ERROR, "Sample rate 8000Hz required for GSM, got %dHz\n",
53 if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
56 if (avctx->bit_rate != 13000 /* Official */ &&
57 avctx->bit_rate != 13200 /* Very common */ &&
58 avctx->bit_rate != 0 /* Unknown; a.o. mov does not set bitrate when decoding */ ) {
59 av_log(avctx, AV_LOG_ERROR, "Bitrate 13000bps required for GSM, got %dbps\n",
61 if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL)
65 avctx->priv_data = gsm_create();
67 switch(avctx->codec_id) {
69 avctx->frame_size = GSM_FRAME_SIZE;
70 avctx->block_align = GSM_BLOCK_SIZE;
72 case AV_CODEC_ID_GSM_MS: {
74 gsm_option(avctx->priv_data, GSM_OPT_WAV49, &one);
75 avctx->frame_size = 2*GSM_FRAME_SIZE;
76 avctx->block_align = GSM_MS_BLOCK_SIZE;
83 static av_cold int libgsm_encode_close(AVCodecContext *avctx) {
84 gsm_destroy(avctx->priv_data);
85 avctx->priv_data = NULL;
89 static int libgsm_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
90 const AVFrame *frame, int *got_packet_ptr)
93 gsm_signal *samples = (gsm_signal *)frame->data[0];
94 struct gsm_state *state = avctx->priv_data;
96 if ((ret = ff_alloc_packet(avpkt, avctx->block_align))) {
97 av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
101 switch(avctx->codec_id) {
102 case AV_CODEC_ID_GSM:
103 gsm_encode(state, samples, avpkt->data);
105 case AV_CODEC_ID_GSM_MS:
106 gsm_encode(state, samples, avpkt->data);
107 gsm_encode(state, samples + GSM_FRAME_SIZE, avpkt->data + 32);
115 AVCodec ff_libgsm_encoder = {
117 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"),
118 .type = AVMEDIA_TYPE_AUDIO,
119 .id = AV_CODEC_ID_GSM,
120 .init = libgsm_encode_init,
121 .encode2 = libgsm_encode_frame,
122 .close = libgsm_encode_close,
123 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
124 AV_SAMPLE_FMT_NONE },
127 AVCodec ff_libgsm_ms_encoder = {
129 .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"),
130 .type = AVMEDIA_TYPE_AUDIO,
131 .id = AV_CODEC_ID_GSM_MS,
132 .init = libgsm_encode_init,
133 .encode2 = libgsm_encode_frame,
134 .close = libgsm_encode_close,
135 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
136 AV_SAMPLE_FMT_NONE },