avformat: add derf demuxer

Changelog

@@ -51,6 +51,7 @@ version <next>:
 - ADPCM IMA MTF decoder
 - FWSE demuxer
 - DERF DPCM decoder
+- DERF demuxer
 
 
 version 4.2:

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-$(CONFIG_DERF_DEMUXER)              += derf.o pcm.o
 OBJS-$(CONFIG_DFA_DEMUXER)               += dfa.o
 OBJS-$(CONFIG_DHAV_DEMUXER)              += dhav.o
 OBJS-$(CONFIG_DIRAC_DEMUXER)             += diracdec.o rawdec.o

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;

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;
+    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",
+};