/* * Copyright (c) 2021 Paul B Mahol * * 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 * AMR audio parser * * Splits packets into individual blocks. */ #include "libavutil/channel_layout.h"#include "libavutil/intreadwrite.h"#include "parser.h" static const uint8_t amrnb_packed_size[16] = {    13, 14, 16, 18, 20, 21, 27, 32, 6, 1, 1, 1, 1, 1, 1, 1};static const uint8_t amrwb_packed_size[16] = {    18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 1, 1, 1, 1, 1, 1}; typedef struct AMRParseContext {    ParseContext pc;    uint64_t cumulated_size;    uint64_t block_count;    int current_channel;    int remaining;} AMRParseContext; static av_cold int amr_parse_init(AVCodecParserContext *s1){    AMRParseContext *s = s1->priv_data;    s->remaining = -1;    return 0;} static int amr_parse(AVCodecParserContext *s1,                     AVCodecContext *avctx,                     const uint8_t **poutbuf, int *poutbuf_size,                     const uint8_t *buf, int buf_size){    AMRParseContext *s = s1->priv_data;    ParseContext *pc = &s->pc;    int next = END_NOT_FOUND;     *poutbuf_size = 0;    *poutbuf = NULL;     if (!avctx->ch_layout.nb_channels) {        av_channel_layout_uninit(&avctx->ch_layout);        avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;    }     if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) {        next = buf_size;    } else {        int ch, offset = 0;         for (ch = s->current_channel; ch < avctx->ch_layout.nb_channels; ch++) {            if (s->remaining >= 0) {                next = s->remaining;            } else {                int mode = (buf[offset] >> 3) & 0x0F;                 if (avctx->codec_id == AV_CODEC_ID_AMR_NB) {                    next = amrnb_packed_size[mode];                } else if (avctx->codec_id == AV_CODEC_ID_AMR_WB) {                    next = amrwb_packed_size[mode];                }            }             offset += next;            if (offset >= buf_size) {                s->remaining = offset - buf_size;                next = END_NOT_FOUND;                break;            } else {                s->remaining = -1;            }        }         s->current_channel = ch % avctx->ch_layout.nb_channels;        if (s->remaining < 0)            next = offset;         if (next != END_NOT_FOUND) {            if (s->cumulated_size < UINT64_MAX - next) {                s->cumulated_size += next;                /* Both AMR formats have 50 frames per second */                avctx->bit_rate = s->cumulated_size / ++s->block_count * 8 * 50;            }        }         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {            *poutbuf      = NULL;            *poutbuf_size = 0;            return buf_size;        }    }     s1->duration = avctx->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;     *poutbuf = buf;    *poutbuf_size = buf_size;    return next;} const AVCodecParser ff_amr_parser = {    .codec_ids      = { AV_CODEC_ID_AMR_NB, AV_CODEC_ID_AMR_WB },    .priv_data_size = sizeof(AMRParseContext),    .parser_init    = amr_parse_init,    .parser_parse   = amr_parse,    .parser_close   = ff_parse_close,};