| 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 | #if HAVE_GSM_H |
| 32 | #include <gsm.h> |
| 33 | #else |
| 34 | #include <gsm/gsm.h> |
| 35 | #endif |
| 36 | |
| 37 | #include "libavutil/channel_layout.h" |
| 38 | #include "libavutil/common.h" |
| 39 | |
| 40 | #include "avcodec.h" |
| 41 | #include "internal.h" |
| 42 | #include "gsm.h" |
| 43 | |
| 44 | typedef struct LibGSMDecodeContext { |
| 45 | struct gsm_state *state; |
| 46 | } LibGSMDecodeContext; |
| 47 | |
| 48 | static av_cold int libgsm_decode_init(AVCodecContext *avctx) { |
| 49 | LibGSMDecodeContext *s = avctx->priv_data; |
| 50 | |
| 51 | avctx->channels = 1; |
| 52 | avctx->channel_layout = AV_CH_LAYOUT_MONO; |
| 53 | if (!avctx->sample_rate) |
| 54 | avctx->sample_rate = 8000; |
| 55 | avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
| 56 | |
| 57 | s->state = gsm_create(); |
| 58 | |
| 59 | switch(avctx->codec_id) { |
| 60 | case AV_CODEC_ID_GSM: |
| 61 | avctx->frame_size = GSM_FRAME_SIZE; |
| 62 | avctx->block_align = GSM_BLOCK_SIZE; |
| 63 | break; |
| 64 | case AV_CODEC_ID_GSM_MS: { |
| 65 | int one = 1; |
| 66 | gsm_option(s->state, GSM_OPT_WAV49, &one); |
| 67 | avctx->frame_size = 2 * GSM_FRAME_SIZE; |
| 68 | avctx->block_align = GSM_MS_BLOCK_SIZE; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | static av_cold int libgsm_decode_close(AVCodecContext *avctx) { |
| 76 | LibGSMDecodeContext *s = avctx->priv_data; |
| 77 | |
| 78 | gsm_destroy(s->state); |
| 79 | s->state = NULL; |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | static int libgsm_decode_frame(AVCodecContext *avctx, void *data, |
| 84 | int *got_frame_ptr, AVPacket *avpkt) |
| 85 | { |
| 86 | int i, ret; |
| 87 | LibGSMDecodeContext *s = avctx->priv_data; |
| 88 | AVFrame *frame = data; |
| 89 | uint8_t *buf = avpkt->data; |
| 90 | int buf_size = avpkt->size; |
| 91 | int16_t *samples; |
| 92 | |
| 93 | if (buf_size < avctx->block_align) { |
| 94 | av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); |
| 95 | return AVERROR_INVALIDDATA; |
| 96 | } |
| 97 | |
| 98 | /* get output buffer */ |
| 99 | frame->nb_samples = avctx->frame_size; |
| 100 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 101 | return ret; |
| 102 | samples = (int16_t *)frame->data[0]; |
| 103 | |
| 104 | for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) { |
| 105 | if ((ret = gsm_decode(s->state, buf, samples)) < 0) |
| 106 | return -1; |
| 107 | buf += GSM_BLOCK_SIZE; |
| 108 | samples += GSM_FRAME_SIZE; |
| 109 | } |
| 110 | |
| 111 | *got_frame_ptr = 1; |
| 112 | |
| 113 | return avctx->block_align; |
| 114 | } |
| 115 | |
| 116 | static void libgsm_flush(AVCodecContext *avctx) { |
| 117 | LibGSMDecodeContext *s = avctx->priv_data; |
| 118 | int one = 1; |
| 119 | |
| 120 | gsm_destroy(s->state); |
| 121 | s->state = gsm_create(); |
| 122 | if (avctx->codec_id == AV_CODEC_ID_GSM_MS) |
| 123 | gsm_option(s->state, GSM_OPT_WAV49, &one); |
| 124 | } |
| 125 | |
| 126 | #if CONFIG_LIBGSM_DECODER |
| 127 | AVCodec ff_libgsm_decoder = { |
| 128 | .name = "libgsm", |
| 129 | .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), |
| 130 | .type = AVMEDIA_TYPE_AUDIO, |
| 131 | .id = AV_CODEC_ID_GSM, |
| 132 | .priv_data_size = sizeof(LibGSMDecodeContext), |
| 133 | .init = libgsm_decode_init, |
| 134 | .close = libgsm_decode_close, |
| 135 | .decode = libgsm_decode_frame, |
| 136 | .flush = libgsm_flush, |
| 137 | .capabilities = CODEC_CAP_DR1, |
| 138 | }; |
| 139 | #endif |
| 140 | #if CONFIG_LIBGSM_MS_DECODER |
| 141 | AVCodec ff_libgsm_ms_decoder = { |
| 142 | .name = "libgsm_ms", |
| 143 | .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), |
| 144 | .type = AVMEDIA_TYPE_AUDIO, |
| 145 | .id = AV_CODEC_ID_GSM_MS, |
| 146 | .priv_data_size = sizeof(LibGSMDecodeContext), |
| 147 | .init = libgsm_decode_init, |
| 148 | .close = libgsm_decode_close, |
| 149 | .decode = libgsm_decode_frame, |
| 150 | .flush = libgsm_flush, |
| 151 | .capabilities = CODEC_CAP_DR1, |
| 152 | }; |
| 153 | #endif |