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authorZixing Liu <liushuyu@aosc.io>2020-09-03 16:32:37 -0600
committerPaul B Mahol <onemda@gmail.com>2020-09-10 17:38:08 +0200
commitd58f8fd8e6b5a6e837c991a065714854edf8448d (patch)
treec794944df462f95695b44504e93a525d9b26e5f9 /libavformat/mca.c
parentc748bd77dcff385e37bb9aaebdf0314d0929d331 (diff)
downloadffmpeg-d58f8fd8e6b5a6e837c991a065714854edf8448d.tar.gz
avformat: add mca demuxer
Signed-off-by: liushuyu <liushuyu@aosc.io>
Diffstat (limited to 'libavformat/mca.c')
-rw-r--r--libavformat/mca.c226
1 files changed, 226 insertions, 0 deletions
diff --git a/libavformat/mca.c b/libavformat/mca.c
new file mode 100644
index 0000000000..f3f34715cb
--- /dev/null
+++ b/libavformat/mca.c
@@ -0,0 +1,226 @@
+/*
+ * 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;
+
+ timestamp /= m->samples_per_block;
+ 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",
+};