[FFmpeg-devel] [PATCH 4/5] avformat: add derf demuxer

[Andreas Rheinhardt]

Paul B Mahol:
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavformat/Makefile     |  1 +
>  libavformat/allformats.c |  1 +
>  libavformat/derf.c       | 79 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 81 insertions(+)
>  create mode 100644 libavformat/derf.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index cd3e9163f5..27615cd746 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -151,6 +151,7 @@ OBJS-$(CONFIG_DASH_DEMUXER)              += dash.o dashdec.o
>  OBJS-$(CONFIG_DAUD_DEMUXER)              += dauddec.o
>  OBJS-$(CONFIG_DAUD_MUXER)                += daudenc.o
>  OBJS-$(CONFIG_DCSTR_DEMUXER)             += dcstr.o
> +OBJS-$(CONFIG_DERF_DEMUXER)              += derf.o
>  OBJS-$(CONFIG_DFA_DEMUXER)               += dfa.o
>  OBJS-$(CONFIG_DHAV_DEMUXER)              += dhav.o
>  OBJS-$(CONFIG_DIRAC_DEMUXER)             += diracdec.o rawdec.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index d275c1017b..af10def88b 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -113,6 +113,7 @@ extern AVOutputFormat ff_data_muxer;
>  extern AVInputFormat  ff_daud_demuxer;
>  extern AVOutputFormat ff_daud_muxer;
>  extern AVInputFormat  ff_dcstr_demuxer;
> +extern AVInputFormat  ff_derf_demuxer;
>  extern AVInputFormat  ff_dfa_demuxer;
>  extern AVInputFormat  ff_dhav_demuxer;
>  extern AVInputFormat  ff_dirac_demuxer;
> diff --git a/libavformat/derf.c b/libavformat/derf.c
> new file mode 100644
> index 0000000000..58bbf5b791
> --- /dev/null
> +++ b/libavformat/derf.c
> @@ -0,0 +1,79 @@
> +/*
> + * DERF 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 "avformat.h"
> +#include "internal.h"
> +#include "pcm.h"
> +
> +static int derf_probe(const AVProbeData *p)
> +{
> +    if (AV_RL32(p->buf) != MKTAG('D','E','R','F'))
> +        return 0;
> +    if (AV_RL32(p->buf+4) != 1 && AV_RL32(p->buf+4) != 2)
> +        return 0;
> +
> +    return AVPROBE_SCORE_MAX / 3 * 2;
> +}
> +
> +static int derf_read_header(AVFormatContext *s)
> +{
> +    unsigned data_size;
> +    AVIOContext *pb = s->pb;
> +    AVCodecParameters *par;
> +    AVStream *st;
> +
> +    avio_skip(pb, 4);
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    par              = st->codecpar;
> +    par->codec_type  = AVMEDIA_TYPE_AUDIO;
> +    par->codec_id    = AV_CODEC_ID_DERF_DPCM;
> +    par->format      = AV_SAMPLE_FMT_S16;
> +    par->channels    = avio_rl32(pb);
> +    if (par->channels != 1 && par->channels != 2)
> +        return AVERROR_INVALIDDATA;
> +    if (par->channels == 1)
> +        par->channel_layout = AV_CH_LAYOUT_MONO;
> +    else if (par->channels == 2)
> +        par->channel_layout = AV_CH_LAYOUT_STEREO;
> +    data_size = avio_rl32(pb);
> +    st->duration = data_size / par->channels;

Won't the reported duration be wrong if the file is trimmed? (Is this
how it is supposed to be?)

> +    par->sample_rate = 22050;
> +    par->block_align = 1;
> +
> +    avpriv_set_pts_info(st, 64, 1, par->sample_rate);
> +
> +    return 0;
> +}
> +
> +AVInputFormat ff_derf_demuxer = {
> +    .name           = "derf",
> +    .long_name      = NULL_IF_CONFIG_SMALL("Xilam DERF"),
> +    .read_probe     = derf_probe,
> +    .read_header    = derf_read_header,
> +    .read_packet    = ff_pcm_read_packet,
> +    .read_seek      = ff_pcm_read_seek,
> +    .extensions     = "adp",
> +};
>