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https://github.com/FFmpeg/FFmpeg.git
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a16577d985
This is essentially a MS GSM decoder extension that supports more sampling rates and lower bitrates. Signed-off-by: Anton Khirnov <anton@khirnov.net>
91 lines
2.5 KiB
C
91 lines
2.5 KiB
C
/*
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* Copyright (c) 2012 Justin Ruggles
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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 audio parser
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*
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* Splits packets into individual blocks.
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*/
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#include "parser.h"
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#include "gsm.h"
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typedef struct GSMParseContext {
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ParseContext pc;
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int block_size;
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int duration;
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int remaining;
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} GSMParseContext;
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static int gsm_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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GSMParseContext *s = s1->priv_data;
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ParseContext *pc = &s->pc;
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int next;
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if (!s->block_size) {
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switch (avctx->codec_id) {
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case AV_CODEC_ID_GSM:
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s->block_size = GSM_BLOCK_SIZE;
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s->duration = GSM_FRAME_SIZE;
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break;
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case AV_CODEC_ID_GSM_MS:
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s->block_size = avctx->block_align ? avctx->block_align
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: GSM_MS_BLOCK_SIZE;
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s->duration = GSM_FRAME_SIZE * 2;
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break;
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default:
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return AVERROR(EINVAL);
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}
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}
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if (!s->remaining)
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s->remaining = s->block_size;
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if (s->remaining <= buf_size) {
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next = s->remaining;
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s->remaining = 0;
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} else {
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next = END_NOT_FOUND;
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s->remaining -= buf_size;
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}
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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s1->duration = s->duration;
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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AVCodecParser ff_gsm_parser = {
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.codec_ids = { AV_CODEC_ID_GSM, AV_CODEC_ID_GSM_MS },
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.priv_data_size = sizeof(GSMParseContext),
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.parser_parse = gsm_parse,
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.parser_close = ff_parse_close,
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};
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