[FFmpeg-devel] [PATCH 2/2] avformat: add fwse demuxer

[Andreas Rheinhardt]

Paul B Mahol:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavformat/Makefile     |  1 +
>  libavformat/allformats.c |  1 +
>  libavformat/fwse.c       | 88 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 90 insertions(+)
>  create mode 100644 libavformat/fwse.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index f84becd30a..cd3e9163f5 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -198,6 +198,7 @@ OBJS-$(CONFIG_FRAMEHASH_MUXER)           += hashenc.o framehash.o
>  OBJS-$(CONFIG_FRAMEMD5_MUXER)            += hashenc.o framehash.o
>  OBJS-$(CONFIG_FRM_DEMUXER)               += frmdec.o
>  OBJS-$(CONFIG_FSB_DEMUXER)               += fsb.o
> +OBJS-$(CONFIG_FWSE_DEMUXER)              += fwse.o
>  OBJS-$(CONFIG_GIF_MUXER)                 += gif.o
>  OBJS-$(CONFIG_GIF_DEMUXER)               += gifdec.o
>  OBJS-$(CONFIG_GSM_DEMUXER)               += gsmdec.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 08012ea208..d275c1017b 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -156,6 +156,7 @@ extern AVOutputFormat ff_framehash_muxer;
>  extern AVOutputFormat ff_framemd5_muxer;
>  extern AVInputFormat  ff_frm_demuxer;
>  extern AVInputFormat  ff_fsb_demuxer;
> +extern AVInputFormat  ff_fwse_demuxer;
>  extern AVInputFormat  ff_g722_demuxer;
>  extern AVOutputFormat ff_g722_muxer;
>  extern AVInputFormat  ff_g723_1_demuxer;
> diff --git a/libavformat/fwse.c b/libavformat/fwse.c
> new file mode 100644
> index 0000000000..76ed6b0c23
> --- /dev/null
> +++ b/libavformat/fwse.c
> @@ -0,0 +1,88 @@
> +/*
> + * FWSE demuxer
> + * Copyright (c) 2020 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
> + */
> +
> +#include "libavutil/intreadwrite.h"
> +#include "libavcodec/internal.h"

What are you using from this header?

> +#include "avformat.h"
> +#include "internal.h"
> +#include "pcm.h"
> +
> +typedef struct FWSEDemuxContext {
> +    unsigned dsp_int_type;
> +    unsigned interleave_size;
> +} FWSEDemuxContext;

This structure is completely unused.
> +
> +static int fwse_probe(const AVProbeData *p)
> +{
> +    if (AV_RL32(p->buf) != MKTAG('F','W','S','E'))
> +        return 0;
> +    if (AV_RL32(p->buf+4) != 2 && AV_RL32(p->buf+4) != 3)
> +        return 0;
> +
> +    return AVPROBE_SCORE_MAX / 3 * 2;
> +}
> +
> +static int fwse_read_header(AVFormatContext *s)
> +{
> +    FWSEDemuxContext *c = s->priv_data;

Doesn't your compiler warn you about unused variables like this one?

> +    unsigned start_offset, version;
> +    AVStream *st;
> +
> +    avio_skip(s->pb, 4);

You're checking the version, yet you are not checking the tag?

> +    version = avio_rl32(s->pb);
> +    if (version != 1 && version != 2)

fwse_probe wants 2 or 3 and here it is 1 or 2.

> +        return AVERROR_INVALIDDATA;
> +    avio_skip(s->pb, 4);
> +    start_offset = avio_rl32(s->pb);
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;

Why don't you access codecpar via its own pointer to reduce the amount
of writing? (You could do the same with s->pb.)

> +    st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_IMA_MTF;
> +    st->codecpar->format      = AV_SAMPLE_FMT_S16;
> +    st->codecpar->channels    = avio_rl32(s->pb);
> +    if (st->codecpar->channels != 1 && st->codecpar->channels != 2)> +        return AVERROR_INVALIDDATA;

Why don't you just add this as another else at the end of the following
checks? (And why don't you check for this during probing?)

> +    if (st->codecpar->channels == 1)
> +        st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
> +    else if (st->codecpar->channels == 2)
> +        st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
> +    st->duration = avio_rl32(s->pb);
> +    st->codecpar->sample_rate = avio_rl32(s->pb);

No check for insane values?

> +    st->codecpar->block_align = 1;
> +    avio_skip(s->pb, start_offset - avio_tell(s->pb));

avio_seek(s->pb, start_offset, SEEK_SET)?
> +
> +    avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
> +
> +    return 0;
> +}
> +
> +AVInputFormat ff_fwse_demuxer = {
> +    .name           = "fwse",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Capcom's MT Framework sound"),
> +    .priv_data_size = sizeof(FWSEDemuxContext),
> +    .read_probe     = fwse_probe,
> +    .read_header    = fwse_read_header,
> +    .read_packet    = ff_pcm_read_packet,
> +    .extensions     = "fwse",
> +};
>