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/*
* AMR Audio decoder stub
* Copyright (c) 2003 the ffmpeg project
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/** @file
* Adaptive Multi-Rate (AMR) Audio decoder stub.
*
* This code implements both an AMR-NarrowBand (AMR-NB) and an AMR-WideBand
* (AMR-WB) audio encoder/decoder through external reference code from
* http://www.3gpp.org/. The license of the code from 3gpp is unclear so you
* have to download the code separately.
*
* \section AMR-NB
*
* The float version (default) can be downloaded from:
* http://www.3gpp.org/ftp/Specs/archive/26_series/26.104/26104-610.zip
*
* \subsection Specification
* The specification for AMR-NB can be found in TS 26.071
* (http://www.3gpp.org/ftp/Specs/html-info/26071.htm) and some other
* info at http://www.3gpp.org/ftp/Specs/html-info/26-series.htm.
*
* \section AMR-WB
*
* The reference code can be downloaded from:
* http://www.3gpp.org/ftp/Specs/archive/26_series/26.204/26204-600.zip
*
* \subsection Specification
* The specification for AMR-WB can be found in TS 26.171
* (http://www.3gpp.org/ftp/Specs/html-info/26171.htm) and some other
* info at http://www.3gpp.org/ftp/Specs/html-info/26-series.htm.
*
*/
#include "avcodec.h"
static void amr_decode_fix_avctx(AVCodecContext *avctx)
{
//const int is_amr_wb = 1 + (avctx->codec_id == CODEC_ID_AMR_WB);
const int is_amr_wb = 1;
if (!avctx->sample_rate)
avctx->sample_rate = 8000 * is_amr_wb;
if (!avctx->channels)
avctx->channels = 1;
avctx->frame_size = 160 * is_amr_wb;
avctx->sample_fmt = SAMPLE_FMT_S16;
}
#if CONFIG_LIBAMR_NB
#include "amr_float/interf_dec.h"
#include "amr_float/interf_enc.h"
static const char nb_bitrate_unsupported[] =
"bitrate not supported: use one of 4.75k, 5.15k, 5.9k, 6.7k, 7.4k, 7.95k, 10.2k or 12.2k\n";
typedef struct AMR_bitrates {
int rate;
enum Mode mode;
} AMR_bitrates;
/* Match desired bitrate */
static int getBitrateMode(int bitrate)
{
/* make the correspondance between bitrate and mode */
AMR_bitrates rates[] = { { 4750, MR475},
{ 5150, MR515},
{ 5900, MR59},
{ 6700, MR67},
{ 7400, MR74},
{ 7950, MR795},
{10200, MR102},
{12200, MR122}, };
int i;
for (i = 0; i < 8; i++)
if (rates[i].rate == bitrate)
return rates[i].mode;
/* no bitrate matching, return an error */
return -1;
}
typedef struct AMRContext {
int frameCount;
void *decState;
int *enstate;
int enc_bitrate;
} AMRContext;
static av_cold int amr_nb_decode_init(AVCodecContext *avctx)
{
AMRContext *s = avctx->priv_data;
s->frameCount = 0;
s->decState = Decoder_Interface_init();
if (!s->decState) {
av_log(avctx, AV_LOG_ERROR, "Decoder_Interface_init error\r\n");
return -1;
}
amr_decode_fix_avctx(avctx);
if (avctx->channels > 1) {
av_log(avctx, AV_LOG_ERROR, "amr_nb: multichannel decoding not supported\n");
return -1;
}
return 0;
}
static av_cold int amr_nb_decode_close(AVCodecContext *avctx)
{
AMRContext *s = avctx->priv_data;
Decoder_Interface_exit(s->decState);
return 0;
}
static int amr_nb_decode_frame(AVCodecContext * avctx, void *data,
int *data_size, const uint8_t * buf, int buf_size)
{
AMRContext *s = avctx->priv_data;
const uint8_t *amrData = buf;
static const uint8_t block_size[16] = { 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0 };
enum Mode dec_mode;
int packet_size;
/* av_log(NULL, AV_LOG_DEBUG, "amr_decode_frame buf=%p buf_size=%d frameCount=%d!!\n",
buf, buf_size, s->frameCount); */
dec_mode = (buf[0] >> 3) & 0x000F;
packet_size = block_size[dec_mode] + 1;
if (packet_size > buf_size) {
av_log(avctx, AV_LOG_ERROR, "amr frame too short (%u, should be %u)\n",
buf_size, packet_size);
return -1;
}
s->frameCount++;
/* av_log(NULL, AV_LOG_DEBUG, "packet_size=%d amrData= 0x%X %X %X %X\n",
packet_size, amrData[0], amrData[1], amrData[2], amrData[3]); */
/* call decoder */
Decoder_Interface_Decode(s->decState, amrData, data, 0);
*data_size = 160 * 2;
return packet_size;
}
AVCodec libamr_nb_decoder = {
"libamr_nb",
CODEC_TYPE_AUDIO,
CODEC_ID_AMR_NB,
sizeof(AMRContext),
amr_nb_decode_init,
NULL,
amr_nb_decode_close,
amr_nb_decode_frame,
/*.capabilities = */0,
/*.next = */NULL,
/*.flush = */NULL,
/*.supported_framerates = */NULL,
/*.pix_fmts = */NULL,
/*.long_name = */NULL_IF_CONFIG_SMALL("libamr-nb Adaptive Multi-Rate (AMR) Narrow-Band"),
};
#endif
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