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