[FFmpeg-devel] [PATCH v2 1/1] avformat: add mca demuxer
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Wed Sep 2 09:37:13 EEST 2020
liushuyu at aosc.io:
> From: Zixing Liu <liushuyu at aosc.io>
>
> Signed-off-by: liushuyu <liushuyu at aosc.io>
> ---
> Changelog | 1 +
> doc/general.texi | 2 +
> libavformat/Makefile | 1 +
> libavformat/allformats.c | 1 +
> libavformat/mca.c | 240 +++++++++++++++++++++++++++++++++++++++
> libavformat/version.h | 4 +-
> 6 files changed, 247 insertions(+), 2 deletions(-)
> create mode 100644 libavformat/mca.c
>
> diff --git a/Changelog b/Changelog
> index 7467e73..ae4219f 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -15,6 +15,7 @@ version <next>:
> - Argonaut Games ASF muxer
> - AV1 Low overhead bitstream format demuxer
> - RPZA video encoder
> +- MCA demuxer
>
>
> version 4.3:
> diff --git a/doc/general.texi b/doc/general.texi
> index d618565..fa76ed4 100644
> --- a/doc/general.texi
> +++ b/doc/general.texi
> @@ -524,6 +524,8 @@ library:
> @tab Metadata in text format.
> @item MAXIS XA @tab @tab X
> @tab Used in Sim City 3000; file extension .xa.
> + at item MCA @tab @tab X
> + @tab Used in some games from Capcom; file extension .mca.
> @item MD Studio @tab @tab X
> @item Metal Gear Solid: The Twin Snakes @tab @tab X
> @item Megalux Frame @tab @tab X
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index cbb33fe..7f5ab21 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -305,6 +305,7 @@ OBJS-$(CONFIG_MATROSKA_MUXER) += matroskaenc.o matroska.o \
> av1.o avc.o hevc.o \
> flacenc_header.o avlanguage.o \
> vorbiscomment.o wv.o
> +OBJS-$(CONFIG_MCA_DEMUXER) += mca.o
> OBJS-$(CONFIG_MCC_DEMUXER) += mccdec.o subtitles.o
> OBJS-$(CONFIG_MD5_MUXER) += hashenc.o
> OBJS-$(CONFIG_MGSTS_DEMUXER) += mgsts.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 0aa9dd7..8a71de6 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -232,6 +232,7 @@ extern AVInputFormat ff_lvf_demuxer;
> extern AVInputFormat ff_lxf_demuxer;
> extern AVInputFormat ff_m4v_demuxer;
> extern AVOutputFormat ff_m4v_muxer;
> +extern AVInputFormat ff_mca_demuxer;
> extern AVInputFormat ff_mcc_demuxer;
> extern AVOutputFormat ff_md5_muxer;
> extern AVInputFormat ff_matroska_demuxer;
> diff --git a/libavformat/mca.c b/libavformat/mca.c
> new file mode 100644
> index 0000000..dbbb374
> --- /dev/null
> +++ b/libavformat/mca.c
> @@ -0,0 +1,240 @@
> +/*
> + * 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 "libavcodec/bytestream.h"
You don't seem to be using anything from this header.
> +#include "avformat.h"
> +#include "internal.h"
> +
> +typedef struct MCADemuxContext {
> + uint32_t block_count;
> + uint16_t block_size;
> + uint32_t coef_offset;
> + 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) <= 0xff)
> + return AVPROBE_SCORE_MAX / 3 * 2;
> + return 0;
> +}
> +
> +static int read_header(AVFormatContext *s)
> +{
> + AVStream *st;
> + MCADemuxContext *m = s->priv_data;
> + int64_t file_size = 0;
> + uint16_t version = 0;
> + uint32_t header_size, data_size, data_offset, loop_start, loop_end,
> + nb_samples, nb_metadata = 0;
> + int ch;
> + int ret = AVERROR_EOF;
This value is never used.
> +
> + st = avformat_new_stream(s, NULL);
> + if (!st)
> + return AVERROR(ENOMEM);
> + st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
If you used a dedicated variable (common name would be par) to access
st->codecpar, the lengths of the lines below would not have outliers.
> +
> + // parse file headers
> + avio_skip(s->pb, 0x4); // skip the file magic
> + version = avio_rl16(s->pb); // offset 0x4
> + avio_skip(s->pb, 0x2); // padding
> + st->codecpar->channels = avio_r8(s->pb); // offset 0x8
> + avio_skip(s->pb, 0x1); // padding
> + m->block_size = avio_rl16(s->pb); // offset 0xa
> + nb_samples = avio_rl32(s->pb); // offset 0xc
> + st->codecpar->sample_rate = avio_rl32(s->pb); // offset 0x10
> + loop_start = avio_rl32(s->pb); // offset 0x14
> + loop_end = avio_rl32(s->pb); // offset 0x18
> + header_size = avio_rl32(s->pb); // offset 0x1c
> + data_size = avio_rl32(s->pb); // offset 0x20
> + avio_skip(s->pb, 0x4); // offset 0x24 (duration, float)
> + nb_metadata = avio_rl16(s->pb); // offset 0x28
> + avio_skip(s->pb, 0x2); // unknown u16 field
You can align these lines on '=' (well, the lines that have a '='). And
I don't think that the offset comments are helpful.
> +
> + file_size = avio_size(s->pb);
> +
You could directly initialize file_size to this value.
> + // samples per frame = 14; frame size = 8 (2^3)
> + m->samples_per_block = (m->block_size * 14) >> 3;
> + m->block_count = nb_samples / m->samples_per_block;
You are dividing by zero here if m->samples_per_block is zero. The check
to rule this out is a few lines below, but that's too late.
> + st->duration = nb_samples;
Is there a reason you prefer this over the duration field you skipped
earlier?
> +
> + // sanity checks
> + if (!st->codecpar->channels || st->codecpar->sample_rate <= 0
> + || m->samples_per_block < 1 || loop_start > loop_end
> + || m->block_count < 1)
> + return AVERROR_INVALIDDATA;
> + if (av_dict_set_int(&s->metadata, "loop_start",
> + av_rescale(loop_start, AV_TIME_BASE,
> + st->codecpar->sample_rate), 0) < 0)
> + return AVERROR(ENOMEM);
Just forward the error.
> + if (av_dict_set_int(&s->metadata, "loop_end",
> + av_rescale(loop_end, AV_TIME_BASE,
> + st->codecpar->sample_rate), 0) < 0)
> + return AVERROR(ENOMEM);
> + avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
> +
> + if (version <= 4) {
> + // version <= 4 needs to use the file size to calculate the offsets
> + if (file_size < 0) {
> + return AVERROR(EIO);
> + }
> + m->data_start = file_size - data_size;
There is no guarantee here that the right hand side is in the range of
uint32_t; same goes for data_offset below.
> + 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
> + data_offset = header_size - 0x30 * st->codecpar->channels - 0x4;
> + ret = avio_seek(s->pb, data_offset, SEEK_SET);
ret needs to be an int64_t for it to hold the return value of avio_seek().
> + if (ret < 0)
> + return ret;
> + m->data_start = avio_rl32(s->pb);
> + // check if the metadata is reasonable
> + if (file_size > 0 && m->data_start + data_size > file_size) {
The addition will be performed as uint32_t (i.e. with wraparound); same
for header_size + data_size below.
> + // the header is broken beyond repair
> + if (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");
Split the string in two lines.
> + m->data_start = file_size - data_size;
> + }
> + } else {
> + avpriv_request_sample(s, "version %d", version);
> + return AVERROR_PATCHWELCOME;
> + }
> +
> + // coefficient alignment = 0x30; metadata size = 0x14
> + m->coef_offset =
> + header_size - 0x30 * st->codecpar->channels + nb_metadata * 0x14;
This is a completely local variable; it should not be in the context.
> + m->current_block = 0;
Your context is initially zeroed before read_header.
> +
> + st->start_time = 0;
> + st->codecpar->codec_id = AV_CODEC_ID_ADPCM_THP_LE;
> +
> + ret = ff_alloc_extradata(st->codecpar, 32 * st->codecpar->channels);
> + if (ret < 0)
> + return ret;
> +
> + ret = avio_seek(s->pb, m->coef_offset, SEEK_SET);
> + if (ret < 0)
> + return ret;
> + for (ch = 0; ch < st->codecpar->channels; ch++) {
> + if (avio_read(s->pb, st->codecpar->extradata + ch * 32, 32) != 32) {
ffio_read_size().
> + return AVERROR_INVALIDDATA;
> + }
> + // 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 that the adpcm audio data is not immediately after the header
where the adpcm audio data
> + ret = avio_seek(s->pb, m->data_start, SEEK_SET);
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> + AVCodecParameters *par = s->streams[0]->codecpar;
> + MCADemuxContext *m = s->priv_data;
> + uint32_t samples, size = 0;
> + int ret, i = 0;
> + uint8_t *dst;
> +
> + if (avio_feof(s->pb))
> + return AVERROR_EOF;
> + m->current_block++;
> + size = m->block_size;
> + samples = m->samples_per_block;
> + // adapted from brstm.c
> + if (m->current_block == m->block_count) {
> + if (samples < size * 14 / 8) {
> + uint32_t adjusted_size = samples / 14 * 8;
> + if (samples % 14)
> + adjusted_size += (samples % 14 + 1) / 2 + 1;
> +
> + size = adjusted_size;
> + }
> + } else if (m->current_block > m->block_count)
> + return AVERROR_EOF;
> +
> + if (size > (INT_MAX - 32 - 4) ||
> + (32 + 4 + size) > (INT_MAX / par->channels) ||
> + (32 + 4 + size) * par->channels > INT_MAX - 8)
> + return AVERROR_INVALIDDATA;
You should check the block_size when reading the header to rule this out.
> + if ((ret = av_new_packet(pkt, size * par->channels)) < 0)
> + return ret;
> + dst = pkt->data;
> + for (i = 0; i < par->channels; i++) {
> + ret = avio_read(s->pb, dst, size);
> + dst += size;
> + if (ret != size) {
> + return AVERROR(EIO);
> + }
> + }
There is really no need to read the data for each channel individually;
the whole thing above can be replaced with av_get_packet().
> + pkt->duration = samples;
> + pkt->stream_index = 0;
> +
> + return ret;
return 0 on success (ret currently contains size).
> +}
> +
> +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",
> +};
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 88876ae..146db09 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -32,8 +32,8 @@
> // Major bumping may affect Ticket5467, 5421, 5451(compatibility with Chromium)
> // Also please add any ticket numbers that you believe might be affected here
> #define LIBAVFORMAT_VERSION_MAJOR 58
> -#define LIBAVFORMAT_VERSION_MINOR 51
> -#define LIBAVFORMAT_VERSION_MICRO 101
> +#define LIBAVFORMAT_VERSION_MINOR 52
> +#define LIBAVFORMAT_VERSION_MICRO 100
>
> #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
> LIBAVFORMAT_VERSION_MINOR, \
>
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