avformat: add demuxer for LEGO Racers' ALP format

Signed-off-by: Zane van Iperen <zane@zanevaniperen.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

1 files changed, 146 insertions, 0 deletions

diff --git a/libavformat/alp.c b/libavformat/alp.c
new file mode 100644
index 0000000000..c0c7905380
--- /dev/null
+++ b/libavformat/alp.c
@@ -0,0 +1,146 @@
+/*
+ * LEGO Racers ALP (.tun & .pcm) demuxer
+ *
+ * Copyright (C) 2020 Zane van Iperen (zane@zanevaniperen.com)
+ *
+ * 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 "avformat.h"
+#include "internal.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/internal.h"
+
+#define ALP_TAG            MKTAG('A', 'L', 'P', ' ')
+#define ALP_MAX_READ_SIZE  4096
+
+typedef struct ALPHeader {
+    uint32_t    magic;          /*< Magic Number, {'A', 'L', 'P', ' '} */
+    uint32_t    header_size;    /*< Header size (after this). */
+    char        adpcm[6];       /*< "ADPCM" */
+    uint8_t     unk1;           /*< Unknown */
+    uint8_t     num_channels;   /*< Channel Count. */
+    uint32_t    sample_rate;    /*< Sample rate, only if header_size >= 12. */
+} ALPHeader;
+
+static int alp_probe(const AVProbeData *p)
+{
+    uint32_t i;
+
+    if (AV_RL32(p->buf) != ALP_TAG)
+        return 0;
+
+    /* Only allowed header sizes are 8 and 12. */
+    i = AV_RL32(p->buf + 4);
+    if (i != 8 && i != 12)
+        return 0;
+
+    if (strncmp("ADPCM", p->buf + 8, 6) != 0)
+        return 0;
+
+    return AVPROBE_SCORE_EXTENSION + 1;
+}
+
+static int alp_read_header(AVFormatContext *s)
+{
+    int ret;
+    AVStream *st;
+    ALPHeader hdr;
+    AVCodecParameters *par;
+
+    if ((hdr.magic = avio_rl32(s->pb)) != ALP_TAG)
+        return AVERROR_INVALIDDATA;
+
+    hdr.header_size = avio_rl32(s->pb);
+
+    if (hdr.header_size != 8 && hdr.header_size != 12) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    if ((ret = avio_read(s->pb, hdr.adpcm, sizeof(hdr.adpcm))) < 0)
+        return ret;
+    else if (ret != sizeof(hdr.adpcm))
+        return AVERROR(EIO);
+
+    if (strncmp("ADPCM", hdr.adpcm, sizeof(hdr.adpcm)) != 0)
+        return AVERROR_INVALIDDATA;
+
+    hdr.unk1                    = avio_r8(s->pb);
+    hdr.num_channels            = avio_r8(s->pb);
+
+    if (hdr.header_size == 8) {
+        /* .TUN music file */
+        hdr.sample_rate         = 11025 * hdr.num_channels;
+    } else {
+        /* .PCM sound file */
+        hdr.sample_rate         = avio_rl32(s->pb);
+    }
+
+    if (hdr.sample_rate > 44100) {
+        avpriv_request_sample(s, "Sample Rate > 44100");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    if (!(st = avformat_new_stream(s, NULL)))
+        return AVERROR(ENOMEM);
+
+    par                         = st->codecpar;
+    par->codec_type             = AVMEDIA_TYPE_AUDIO;
+    par->codec_id               = AV_CODEC_ID_ADPCM_IMA_ALP;
+    par->format                 = AV_SAMPLE_FMT_S16;
+    par->sample_rate            = hdr.sample_rate;
+    par->channels               = hdr.num_channels;
+
+    if (hdr.num_channels == 1)
+        par->channel_layout     = AV_CH_LAYOUT_MONO;
+    else if (hdr.num_channels == 2)
+        par->channel_layout     = AV_CH_LAYOUT_STEREO;
+    else
+        return AVERROR_INVALIDDATA;
+
+    par->bits_per_coded_sample  = 4;
+    par->bits_per_raw_sample    = 16;
+    par->block_align            = 1;
+    par->bit_rate               = par->channels *
+                                  par->sample_rate *
+                                  par->bits_per_coded_sample;
+
+    avpriv_set_pts_info(st, 64, 1, par->sample_rate);
+    return 0;
+}
+
+static int alp_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int ret;
+    AVCodecParameters *par = s->streams[0]->codecpar;
+
+    if ((ret = av_get_packet(s->pb, pkt, ALP_MAX_READ_SIZE)) < 0)
+        return ret;
+
+    pkt->flags         &= ~AV_PKT_FLAG_CORRUPT;
+    pkt->stream_index   = 0;
+    pkt->duration       = ret * 2 / par->channels;
+
+    return 0;
+}
+
+AVInputFormat ff_alp_demuxer = {
+    .name           = "alp",
+    .long_name      = NULL_IF_CONFIG_SMALL("LEGO Racers ALP"),
+    .read_probe     = alp_probe,
+    .read_header    = alp_read_header,
+    .read_packet    = alp_read_packet
+};