mirror of
https://github.com/FFmpeg/FFmpeg.git
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119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/*
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* gsm 06.10 decoder
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* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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*
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* This file is part of Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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* GSM decoder
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*/
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#include "avcodec.h"
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#include "get_bits.h"
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#include "msgsmdec.h"
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#include "gsmdec_template.c"
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static av_cold int gsm_init(AVCodecContext *avctx)
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{
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avctx->channels = 1;
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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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switch (avctx->codec_id) {
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case 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 CODEC_ID_GSM_MS:
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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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return 0;
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}
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static int gsm_decode_frame(AVCodecContext *avctx, void *data,
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int *data_size, AVPacket *avpkt)
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{
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int res;
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GetBitContext gb;
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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int16_t *samples = data;
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int frame_bytes = avctx->frame_size *
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av_get_bytes_per_sample(avctx->sample_fmt);
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if (*data_size < frame_bytes) {
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av_log(avctx, AV_LOG_ERROR, "Output buffer is too small\n");
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return AVERROR(EINVAL);
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}
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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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switch (avctx->codec_id) {
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case CODEC_ID_GSM:
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init_get_bits(&gb, buf, buf_size * 8);
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if (get_bits(&gb, 4) != 0xd)
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av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
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res = gsm_decode_block(avctx, samples, &gb);
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if (res < 0)
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return res;
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break;
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case CODEC_ID_GSM_MS:
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res = ff_msgsm_decode_block(avctx, samples, buf);
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if (res < 0)
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return res;
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}
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*data_size = frame_bytes;
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return avctx->block_align;
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}
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static void gsm_flush(AVCodecContext *avctx)
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{
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GSMContext *s = avctx->priv_data;
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memset(s, 0, sizeof(*s));
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}
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AVCodec ff_gsm_decoder = {
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.name = "gsm",
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.type = AVMEDIA_TYPE_AUDIO,
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.id = CODEC_ID_GSM,
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.priv_data_size = sizeof(GSMContext),
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.init = gsm_init,
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.decode = gsm_decode_frame,
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.flush = gsm_flush,
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.long_name = NULL_IF_CONFIG_SMALL("GSM"),
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};
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AVCodec ff_gsm_ms_decoder = {
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.name = "gsm_ms",
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.type = AVMEDIA_TYPE_AUDIO,
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.id = CODEC_ID_GSM_MS,
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.priv_data_size = sizeof(GSMContext),
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.init = gsm_init,
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.decode = gsm_decode_frame,
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.flush = gsm_flush,
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.long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
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};
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