| /* |
| * 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, |
| }; |