[libav-stable] vocdec: Don't update codec parameters mid-stream

Martin Storsjö git at libav.org
Mon Sep 16 10:26:29 CEST 2013


Module: libav
Branch: master
Commit: 5bbfe193a0a41bd2adb648c8c3f6901a575734a2

Author:    Martin Storsjö <martin at martin.st>
Committer: Martin Storsjö <martin at martin.st>
Date:      Thu Sep 12 11:31:53 2013 +0300

vocdec: Don't update codec parameters mid-stream

If we really want to support parameter changes, they need to be
signalled along with the AVPackets as parameter change side data,
not just changing the AVCodecContext parameters when a packet
is demuxed (since there may be other earlier packets yet undecoded).

Something similar was already done for the sample rate in 0883109b2,
but some parameters were left changeable.

This avoids having to recheck the channel count for validity for
each decoded frame in (ad)pcm decoders, unless the decoders
explicitly say that they accept parameter changes.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
Signed-off-by: Martin Storsjö <martin at martin.st>

---

 libavformat/vocdec.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libavformat/vocdec.c b/libavformat/vocdec.c
index 4e06513..2fb8440 100644
--- a/libavformat/vocdec.c
+++ b/libavformat/vocdec.c
@@ -91,11 +91,11 @@ ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
                 if (sample_rate)
                     dec->sample_rate = sample_rate;
                 avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
+                dec->channels = channels;
+                dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);
             } else
                 avio_skip(pb, 1);
-            dec->channels = channels;
             tmp_codec = avio_r8(pb);
-            dec->bits_per_coded_sample = av_get_bits_per_sample(dec->codec_id);
             voc->remaining_size -= 2;
             max_size -= 2;
             channels = 1;
@@ -117,10 +117,10 @@ ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
             if (!dec->sample_rate) {
                 dec->sample_rate = avio_rl32(pb);
                 avpriv_set_pts_info(st, 64, 1, dec->sample_rate);
+                dec->bits_per_coded_sample = avio_r8(pb);
+                dec->channels = avio_r8(pb);
             } else
-                avio_skip(pb, 4);
-            dec->bits_per_coded_sample = avio_r8(pb);
-            dec->channels = avio_r8(pb);
+                avio_skip(pb, 6);
             tmp_codec = avio_rl16(pb);
             avio_skip(pb, 4);
             voc->remaining_size -= 12;



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