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

Paul B Mahol onemda at gmail.com
Sun Mar 15 12:51:59 EET 2020


On 3/15/20, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> 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?)

Yes.

>
>> +    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",
>> +};
>>
>
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