[FFmpeg-devel] [PATCH 2/2] AST demuxer

[Paul B Mahol]

Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
 doc/general.texi         |   2 +
 libavformat/Makefile     |   1 +
 libavformat/allformats.c |   1 +
 libavformat/ast.c        | 115 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 119 insertions(+)
 create mode 100644 libavformat/ast.c

diff --git a/doc/general.texi b/doc/general.texi
index 28f813e..951df8e 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -148,6 +148,8 @@ library:
 @item Apple HTTP Live Streaming @tab   @tab X
 @item Artworx Data Format       @tab   @tab X
 @item ASF                       @tab X @tab X
+ at item AST                       @tab   @tab X
+    @tab Used on the Nintendo Wii.
 @item AVI                       @tab X @tab X
 @item AVISynth                  @tab   @tab X
 @item AVR                       @tab   @tab X
diff --git a/libavformat/Makefile b/libavformat/Makefile
index cf3aae2..136ada8 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -50,6 +50,7 @@ OBJS-$(CONFIG_ASF_DEMUXER)               += asfdec.o asf.o asfcrypt.o \
 OBJS-$(CONFIG_ASF_MUXER)                 += asfenc.o asf.o
 OBJS-$(CONFIG_ASS_DEMUXER)               += assdec.o
 OBJS-$(CONFIG_ASS_MUXER)                 += assenc.o
+OBJS-$(CONFIG_AST_DEMUXER)               += ast.o
 OBJS-$(CONFIG_AU_DEMUXER)                += au.o pcm.o
 OBJS-$(CONFIG_AU_MUXER)                  += au.o
 OBJS-$(CONFIG_AVI_DEMUXER)               += avidec.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 88b4e1b..d08c134 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -64,6 +64,7 @@ void av_register_all(void)
     REGISTER_DEMUXER  (APE, ape);
     REGISTER_MUXDEMUX (ASF, asf);
     REGISTER_MUXDEMUX (ASS, ass);
+    REGISTER_DEMUXER  (AST, ast);
     REGISTER_MUXER    (ASF_STREAM, asf_stream);
     REGISTER_MUXDEMUX (AU, au);
     REGISTER_MUXDEMUX (AVI, avi);
diff --git a/libavformat/ast.c b/libavformat/ast.c
new file mode 100644
index 0000000..ed55e02
--- /dev/null
+++ b/libavformat/ast.c
@@ -0,0 +1,115 @@
+/*
+ * AST demuxer
+ * Copyright (c) 2012 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/channel_layout.h"
+#include "libavutil/intreadwrite.h"
+#include "avformat.h"
+#include "internal.h"
+
+static int ast_probe(AVProbeData *p)
+{
+    if (AV_RL32(p->buf) == MKTAG('S', 'T', 'R', 'M'))
+        return AVPROBE_SCORE_MAX / 2;
+    return 0;
+}
+
+static int ast_read_header(AVFormatContext *s)
+{
+    int codec;
+    AVStream *st;
+
+    st = avformat_new_stream(s, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    avio_skip(s->pb, 8);
+    codec = avio_rb16(s->pb);
+    switch (codec) {
+    case 1:
+        st->codec->codec_id = AV_CODEC_ID_PCM_S16BE_PLANAR;
+        break;
+    default:
+        av_log(s, AV_LOG_ERROR, "unsupported codec %d\n", codec);
+    }
+
+    avio_skip(s->pb, 2);
+
+    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+    st->codec->channels = avio_rb16(s->pb);
+    if (!st->codec->channels)
+        return AVERROR_INVALIDDATA;
+
+    if (st->codec->channels == 2)
+        st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
+    else if (st->codec->channels == 4)
+        st->codec->channel_layout = AV_CH_LAYOUT_4POINT0;
+
+    avio_skip(s->pb, 2);
+    st->codec->sample_rate = avio_rb32(s->pb);
+    st->start_time         = 0;
+    st->duration           = avio_rb32(s->pb);
+    avio_skip(s->pb, 40);
+    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
+
+    return 0;
+}
+
+static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    uint32_t type, size;
+    int64_t pos;
+    int ret;
+
+    if (url_feof(s->pb))
+        return AVERROR_EOF;
+
+    pos  = avio_tell(s->pb);
+    type = avio_rl32(s->pb);
+    size = avio_rb32(s->pb);
+    if (size > INT_MAX / s->streams[0]->codec->channels)
+        return AVERROR_INVALIDDATA;
+
+    size *= s->streams[0]->codec->channels;
+    if ((ret = avio_skip(s->pb, 24)) < 0) // padding
+        return ret;
+
+    if (type == MKTAG('B','L','C','K')) {
+        ret = av_get_packet(s->pb, pkt, size);
+        pkt->stream_index = 0;
+        pkt->pos = pos;
+    } else {
+        av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type);
+        avio_skip(s->pb, size);
+        ret = AVERROR_INVALIDDATA;
+    }
+
+    return ret;
+}
+
+AVInputFormat ff_ast_demuxer = {
+    .name           = "ast",
+    .long_name      = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
+    .read_probe     = ast_probe,
+    .read_header    = ast_read_header,
+    .read_packet    = ast_read_packet,
+    .extensions     = "ast",
+    .flags          = AVFMT_GENERIC_INDEX,
+};
-- 
1.7.11.4