/* * Interface to libgsm for GSM decoding * Copyright (c) 2005 Alban Bedel * Copyright (c) 2006, 2007 Michel Bardiaux * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Interface to libgsm for GSM decoding */ // The idiosyncrasies of GSM-in-WAV are explained at http://kbs.cs.tu-berlin.de/~jutta/toast.html #include #include "libavutil/channel_layout.h" #include "libavutil/common.h" #include "avcodec.h" #include "internal.h" #include "gsm.h" typedef struct LibGSMDecodeContext { struct gsm_state *state; } LibGSMDecodeContext; static av_cold int libgsm_decode_init(AVCodecContext *avctx) { LibGSMDecodeContext *s = avctx->priv_data; avctx->channels = 1; avctx->channel_layout = AV_CH_LAYOUT_MONO; avctx->sample_rate = 8000; avctx->sample_fmt = AV_SAMPLE_FMT_S16; s->state = gsm_create(); switch(avctx->codec_id) { case AV_CODEC_ID_GSM: avctx->frame_size = GSM_FRAME_SIZE; avctx->block_align = GSM_BLOCK_SIZE; break; case AV_CODEC_ID_GSM_MS: { int one = 1; gsm_option(s->state, GSM_OPT_WAV49, &one); avctx->frame_size = 2 * GSM_FRAME_SIZE; avctx->block_align = GSM_MS_BLOCK_SIZE; } } return 0; } static av_cold int libgsm_decode_close(AVCodecContext *avctx) { LibGSMDecodeContext *s = avctx->priv_data; gsm_destroy(s->state); s->state = NULL; return 0; } static int libgsm_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt) { int i, ret; LibGSMDecodeContext *s = avctx->priv_data; AVFrame *frame = data; uint8_t *buf = avpkt->data; int buf_size = avpkt->size; int16_t *samples; if (buf_size < avctx->block_align) { av_log(avctx, AV_LOG_ERROR, "Packet is too small\n"); return AVERROR_INVALIDDATA; } /* get output buffer */ frame->nb_samples = avctx->frame_size; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } samples = (int16_t *)frame->data[0]; for (i = 0; i < avctx->frame_size / GSM_FRAME_SIZE; i++) { if ((ret = gsm_decode(s->state, buf, samples)) < 0) return -1; buf += GSM_BLOCK_SIZE; samples += GSM_FRAME_SIZE; } *got_frame_ptr = 1; return avctx->block_align; } static void libgsm_flush(AVCodecContext *avctx) { LibGSMDecodeContext *s = avctx->priv_data; int one = 1; gsm_destroy(s->state); s->state = gsm_create(); if (avctx->codec_id == AV_CODEC_ID_GSM_MS) gsm_option(s->state, GSM_OPT_WAV49, &one); } AVCodec ff_libgsm_decoder = { .name = "libgsm", .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM"), .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_GSM, .priv_data_size = sizeof(LibGSMDecodeContext), .init = libgsm_decode_init, .close = libgsm_decode_close, .decode = libgsm_decode_frame, .flush = libgsm_flush, .capabilities = AV_CODEC_CAP_DR1, }; AVCodec ff_libgsm_ms_decoder = { .name = "libgsm_ms", .long_name = NULL_IF_CONFIG_SMALL("libgsm GSM Microsoft variant"), .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_GSM_MS, .priv_data_size = sizeof(LibGSMDecodeContext), .init = libgsm_decode_init, .close = libgsm_decode_close, .decode = libgsm_decode_frame, .flush = libgsm_flush, .capabilities = AV_CODEC_CAP_DR1, };