In many older QuickTime files, the audio format, or "fourcc", is
0x00000000 (AV_CODEC_ID_NONE). The QuickTime File Format Specification
states the following regarding this situation:
"This format descriptor should not be used, but may be found in some
files. Samples are assumed to be stored in either 'raw ' or 'twos'
format, depending on the sample size field in the sound description."
MPlayer handles this logic by itself, but FFmpeg/FFplay currently does
not.
I have also removed some superfluous checks for the format/fourcc at the
very start of the private data for A_QUICKTIME and V_QUICKTIME. This
shouldn't happen, since the private data always starts with the sample
description size, *then* the format/fourcc, in a Matroska file.
Mats
--
Mats Peterson
http://matsp888.no-ip.org/~mats/
>From 2783742601db6bb19d8571f013a5ec6902201e83 Mon Sep 17 00:00:00 2001
From: Mats Peterson <matsp...@yahoo.com>
Date: Mon, 4 Jan 2016 21:38:34 +0100
Subject: [PATCH] lavf/matroskadec: A_QUICKTIME and AV_CODEC_ID_NONE
In many older QuickTime files, the audio format, or "fourcc", is
0x00000000 (AV_CODEC_ID_NONE). The QuickTime File Format Specification
states the following regarding this situation:
"This format descriptor should not be used, but may be found in some
files. Samples are assumed to be stored in either 'raw ' or 'twos'
format, depending on the sample size field in the sound description."
MPlayer handles this logic by itself, but FFmpeg/FFplay currently does
not.
I have also removed some superfluous checks for the format/fourcc at the
very start of the private data for A_QUICKTIME and V_QUICKTIME. This
shouldn't happen, since the private data always starts with the sample
description size, *then* the format/fourcc, in a Matroska file.
Mats
---
libavformat/matroskadec.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 9de7cfb..aaac620 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1865,19 +1865,20 @@ static int matroska_parse_tracks(AVFormatContext *s)
&& (track->codec_priv.data)) {
fourcc = AV_RL32(track->codec_priv.data + 4);
codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movaudio_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
+ if (codec_id == AV_CODEC_ID_NONE) {
+ if (track->audio.bitdepth == 8) {
+ fourcc = MKTAG('r','a','w',' ');
+ codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
+ } else if (track->audio.bitdepth == 16) {
+ fourcc = MKTAG('t','w','o','s');
+ codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
+ }
}
} else if (!strcmp(track->codec_id, "V_QUICKTIME") &&
(track->codec_priv.size >= 21) &&
(track->codec_priv.data)) {
fourcc = AV_RL32(track->codec_priv.data + 4);
codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movvideo_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- }
if (codec_id == AV_CODEC_ID_NONE && AV_RL32(track->codec_priv.data+4) == AV_RL32("SMI "))
codec_id = AV_CODEC_ID_SVQ3;
if (codec_id == AV_CODEC_ID_NONE) {
--
1.7.10.4
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