avformat/vag: fix demuxing stereo files

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/vag.c

@@ -23,10 +23,6 @@
 #include "avformat.h"
 #include "internal.h"
 
-typedef struct VAGDemuxContext {
-    int64_t data_end;
-} VAGDemuxContext;
-
 static int vag_probe(AVProbeData *p)
 {
     if (memcmp(p->buf, "VAGp\0\0\0", 7))
@@ -37,8 +33,8 @@ static int vag_probe(AVProbeData *p)
 
 static int vag_read_header(AVFormatContext *s)
 {
-    VAGDemuxContext *c = s->priv_data;
     AVStream *st;
+    int64_t pos;
 
     st = avformat_new_stream(s, NULL);
     if (!st)
@@ -49,13 +45,24 @@ static int vag_read_header(AVFormatContext *s)
     st->codec->codec_id    = AV_CODEC_ID_ADPCM_PSX;
     st->codec->channels    = 1 + (avio_rb32(s->pb) == 0x00000004);
     avio_skip(s->pb, 4);
-    c->data_end            = avio_rb32(s->pb);
-    st->duration           = (c->data_end - avio_tell(s->pb)) / (16 * st->codec->channels) * 28;
+    if (st->codec->channels > 1) {
+        st->duration       = avio_rb32(s->pb);
+    } else {
+        st->duration       = avio_rb32(s->pb) / 16 * 28;
+    }
     st->codec->sample_rate = avio_rb32(s->pb);
     if (st->codec->sample_rate <= 0)
         return AVERROR_INVALIDDATA;
-    st->codec->block_align = 16 * st->codec->channels;
-    avio_skip(s->pb, 28);
+    pos = avio_tell(s->pb);
+    avio_seek(s->pb, 0x1000, SEEK_SET);
+    if (avio_rl32(s->pb) == MKTAG('V','A','G','p')) {
+        st->codec->block_align = 0x1000 * st->codec->channels;
+        avio_seek(s->pb, 0, SEEK_SET);
+        st->duration = st->duration / 16 * 28;
+    } else {
+        st->codec->block_align = 16 * st->codec->channels;
+        avio_seek(s->pb, st->codec->channels > 1 ? 0x80 : 0x30, SEEK_SET);
+    }
     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
 
     return 0;
@@ -63,21 +70,14 @@ static int vag_read_header(AVFormatContext *s)
 
 static int vag_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
-    VAGDemuxContext *c = s->priv_data;
     AVCodecContext *codec = s->streams[0]->codec;
-    int size;
-
-    size = FFMIN(c->data_end - avio_tell(s->pb), codec->block_align);
-    if (size <= 0)
-        return AVERROR_EOF;
 
-    return av_get_packet(s->pb, pkt, size);
+    return av_get_packet(s->pb, pkt, codec->block_align);
 }
 
 AVInputFormat ff_vag_demuxer = {
     .name           = "vag",
     .long_name      = NULL_IF_CONFIG_SMALL("Sony VAG"),
-    .priv_data_size = sizeof(VAGDemuxContext),
     .read_probe     = vag_probe,
     .read_header    = vag_read_header,
     .read_packet    = vag_read_packet,