| /* |
| * MCA demuxer |
| * Copyright (c) 2020 Zixing Liu |
| * |
| * 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 |
| */ |
| |
| #include "libavutil/intreadwrite.h" |
| #include "avformat.h" |
| #include "avio_internal.h" |
| #include "internal.h" |
| |
| typedef struct MCADemuxContext { |
| uint32_t block_count; |
| uint16_t block_size; |
| uint32_t current_block; |
| uint32_t data_start; |
| uint32_t samples_per_block; |
| } MCADemuxContext; |
| |
| static int probe(const AVProbeData *p) |
| { |
| if (AV_RL32(p->buf) == MKTAG('M', 'A', 'D', 'P') && |
| AV_RL16(p->buf + 4) <= 0x5) |
| return AVPROBE_SCORE_MAX / 3 * 2; |
| return 0; |
| } |
| |
| static int read_header(AVFormatContext *s) |
| { |
| AVStream *st; |
| MCADemuxContext *m = s->priv_data; |
| AVCodecParameters *par; |
| int64_t file_size = avio_size(s->pb); |
| uint16_t version = 0; |
| uint32_t header_size, data_size, data_offset, loop_start, loop_end, |
| nb_samples, nb_metadata, coef_offset = 0; |
| int ch, ret; |
| int64_t ret_size; |
| |
| st = avformat_new_stream(s, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| par = st->codecpar; |
| par->codec_type = AVMEDIA_TYPE_AUDIO; |
| |
| // parse file headers |
| avio_skip(s->pb, 0x4); // skip the file magic |
| version = avio_rl16(s->pb); |
| avio_skip(s->pb, 0x2); // padding |
| par->channels = avio_r8(s->pb); |
| avio_skip(s->pb, 0x1); // padding |
| m->block_size = avio_rl16(s->pb); |
| nb_samples = avio_rl32(s->pb); |
| par->sample_rate = avio_rl32(s->pb); |
| loop_start = avio_rl32(s->pb); |
| loop_end = avio_rl32(s->pb); |
| header_size = avio_rl32(s->pb); |
| data_size = avio_rl32(s->pb); |
| avio_skip(s->pb, 0x4); |
| nb_metadata = avio_rl16(s->pb); |
| avio_skip(s->pb, 0x2); // unknown u16 field |
| |
| // samples per frame = 14; frame size = 8 (2^3) |
| m->samples_per_block = (m->block_size * 14) >> 3; |
| |
| if (m->samples_per_block < 1) |
| return AVERROR_INVALIDDATA; |
| |
| m->block_count = nb_samples / m->samples_per_block; |
| st->duration = nb_samples; |
| |
| // sanity checks |
| if (!par->channels || par->sample_rate <= 0 |
| || loop_start > loop_end || m->block_count < 1) |
| return AVERROR_INVALIDDATA; |
| if ((ret = av_dict_set_int(&s->metadata, "loop_start", |
| av_rescale(loop_start, AV_TIME_BASE, |
| par->sample_rate), 0)) < 0) |
| return ret; |
| if ((ret = av_dict_set_int(&s->metadata, "loop_end", |
| av_rescale(loop_end, AV_TIME_BASE, |
| par->sample_rate), 0)) < 0) |
| return ret; |
| if ((32 + 4 + m->block_size) > (INT_MAX / par->channels) || |
| (32 + 4 + m->block_size) * par->channels > INT_MAX - 8) |
| return AVERROR_INVALIDDATA; |
| avpriv_set_pts_info(st, 64, 1, par->sample_rate); |
| |
| if (version <= 4) { |
| // version <= 4 needs to use the file size to calculate the offsets |
| if (file_size < 0) { |
| return AVERROR(EIO); |
| } |
| if (file_size - data_size > UINT32_MAX) |
| return AVERROR_INVALIDDATA; |
| m->data_start = file_size - data_size; |
| if (version <= 3) { |
| nb_metadata = 0; |
| // header_size is not available or incorrect in older versions |
| header_size = m->data_start; |
| } |
| } else if (version == 5) { |
| // read data_start location from the header |
| if (0x30 * par->channels + 0x4 > header_size) |
| return AVERROR_INVALIDDATA; |
| data_offset = header_size - 0x30 * par->channels - 0x4; |
| if ((ret_size = avio_seek(s->pb, data_offset, SEEK_SET)) < 0) |
| return ret_size; |
| m->data_start = avio_rl32(s->pb); |
| // check if the metadata is reasonable |
| if (file_size > 0 && (int64_t)m->data_start + data_size > file_size) { |
| // the header is broken beyond repair |
| if ((int64_t)header_size + data_size > file_size) { |
| av_log(s, AV_LOG_ERROR, |
| "MCA metadata corrupted, unable to determine the data offset.\n"); |
| return AVERROR_INVALIDDATA; |
| } |
| // recover the data_start information from the data size |
| av_log(s, AV_LOG_WARNING, |
| "Incorrect header size found in metadata, " |
| "header size approximated from the data size\n"); |
| if (file_size - data_offset > UINT32_MAX) |
| return AVERROR_INVALIDDATA; |
| m->data_start = file_size - data_size; |
| } |
| } else { |
| avpriv_request_sample(s, "version %d", version); |
| return AVERROR_PATCHWELCOME; |
| } |
| |
| // coefficient alignment = 0x30; metadata size = 0x14 |
| if (0x30 * par->channels + nb_metadata * 0x14 > header_size) |
| return AVERROR_INVALIDDATA; |
| coef_offset = |
| header_size - 0x30 * par->channels + nb_metadata * 0x14; |
| |
| st->start_time = 0; |
| par->codec_id = AV_CODEC_ID_ADPCM_THP_LE; |
| |
| ret = ff_alloc_extradata(st->codecpar, 32 * par->channels); |
| if (ret < 0) |
| return ret; |
| |
| if ((ret_size = avio_seek(s->pb, coef_offset, SEEK_SET)) < 0) |
| return ret_size; |
| for (ch = 0; ch < par->channels; ch++) { |
| if ((ret = ffio_read_size(s->pb, par->extradata + ch * 32, 32)) < 0) |
| return ret; |
| // 0x30 (alignment) - 0x20 (actual size, 32) = 0x10 (padding) |
| avio_skip(s->pb, 0x10); |
| } |
| |
| // seek to the beginning of the adpcm data |
| // there are some files where the adpcm audio data is not immediately after the header |
| if ((ret_size = avio_seek(s->pb, m->data_start, SEEK_SET)) < 0) |
| return ret_size; |
| |
| return 0; |
| } |
| |
| static int read_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| AVCodecParameters *par = s->streams[0]->codecpar; |
| MCADemuxContext *m = s->priv_data; |
| uint16_t size = m->block_size; |
| uint32_t samples = m->samples_per_block; |
| int ret = 0; |
| |
| if (avio_feof(s->pb)) |
| return AVERROR_EOF; |
| m->current_block++; |
| if (m->current_block > m->block_count) |
| return AVERROR_EOF; |
| |
| if ((ret = av_get_packet(s->pb, pkt, size * par->channels)) < 0) |
| return ret; |
| pkt->duration = samples; |
| pkt->stream_index = 0; |
| |
| return 0; |
| } |
| |
| static int read_seek(AVFormatContext *s, int stream_index, |
| int64_t timestamp, int flags) |
| { |
| AVStream *st = s->streams[stream_index]; |
| MCADemuxContext *m = s->priv_data; |
| int64_t ret = 0; |
| |
| if (timestamp < 0) |
| timestamp = 0; |
| timestamp /= m->samples_per_block; |
| if (timestamp >= m->block_count) |
| timestamp = m->block_count - 1; |
| ret = avio_seek(s->pb, m->data_start + timestamp * m->block_size * |
| st->codecpar->channels, SEEK_SET); |
| if (ret < 0) |
| return ret; |
| |
| m->current_block = timestamp; |
| ff_update_cur_dts(s, st, timestamp * m->samples_per_block); |
| return 0; |
| } |
| |
| AVInputFormat ff_mca_demuxer = { |
| .name = "mca", |
| .long_name = NULL_IF_CONFIG_SMALL("MCA Audio Format"), |
| .priv_data_size = sizeof(MCADemuxContext), |
| .read_probe = probe, |
| .read_header = read_header, |
| .read_packet = read_packet, |
| .read_seek = read_seek, |
| .extensions = "mca", |
| }; |