[FFmpeg-devel] [PATCH] Fix start_time in MKV Demuxer

[Michael Niedermayer]

On Wed, Dec 18, 2013 at 06:47:10PM -0800, Alex Sukhanov wrote:
> Problem:
> MKV demuxer explicitly set previously start_time = 0. So in case if first timestamp of video file > 0, update_initial_timestamps() located inlibavformat/utils.c, didn't update start time.
> 
> How to reproduce:
> $ffprobe chunk_00180.flv
> $ffprobe chunk_00180.mkv 
> 
> It's the same video but packed into FLV and MKV containers
> 
> FLV: Duration: 00:02:30.54, start: 150.000000, bitrate: 50 kb/s
> MKV: Duration: 00:02:30.54, start: 0.000000, bitrate: 50 kb/s
> 
> Fix:
> drop line in MKV demuxer which sets start_time = 0
> 
> TESTED:
> FATE passed (I had to modify expectations of some tests)
[...]
> diff --git a/tests/ref/fate/vp9-parallelmode-akiyo b/tests/ref/fate/vp9-parallelmode-akiyo
> index 9668c54..0591e2c 100644
> --- a/tests/ref/fate/vp9-parallelmode-akiyo
> +++ b/tests/ref/fate/vp9-parallelmode-akiyo
> @@ -10,21 +10,21 @@
>  0,          4,          4,        1,   152064, 6719f3a6c22f05dc53dd3906e4154bd7
>  0,          5,          5,        1,   152064, 8cd9a12761e35f67c278949cd3aee88f
>  0,          6,          6,        1,   152064, 8cd9a12761e35f67c278949cd3aee88f
> -0,          7,          7,        1,   152064, 0160dec415234d39f148e91f72d264ab
> -0,          8,          8,        1,   152064, 9f90d96d67d9e9b3716abe2a3faa854e
> -0,          9,          9,        1,   152064, 1edb312f9d0be7835b964a3ffa014759
> -0,         10,         10,        1,   152064, 7614fd674609afccacd355aa2f714c75
> -0,         11,         11,        1,   152064, cb46868706dd246878bebf354aff66f4
> -0,         12,         12,        1,   152064, da36fe96cb4956036f890bb2f6d05b98
> -0,         13,         13,        1,   152064, af0a178c68b719b369c8fa8537d38e65
> -0,         14,         14,        1,   152064, ff03dbc436376fc60ac240cd6c4fc518
> -0,         15,         15,        1,   152064, b0bf25e139556bd9067616db7e4f47b5
> -0,         16,         16,        1,   152064, e70d5480c1f82fc877bbe1a8093f807a
> -0,         17,         17,        1,   152064, 622fb43e6ff63834f0f680a68b49f6e6
> -0,         18,         18,        1,   152064, c331ebba15f2290f174533dbffb3c27b
> -0,         19,         19,        1,   152064, 15cb153425c55f7065fb36606c48972e
> -0,         20,         20,        1,   152064, b95c7699639c51b08b3615ef7fa7046c
> -0,         21,         21,        1,   152064, b4774148c71c9c184bda5a18294e459c
> -0,         22,         22,        1,   152064, 795b7ce4c5e0dc343bd8f80ad6c1a454
> -0,         23,         23,        1,   152064, 19163601b7b6138e2940cf28f6df6c7f
> -0,         24,         24,        1,   152064, b9b388e0892c52df0680a30bfa954506
> +0,          7,          7,        1,   152064, 32841e8b6916f1daea7ef1b980da1710
> +0,          8,          8,        1,   152064, d959ebaa0f45cdf93caac47cb22621ff
> +0,          9,          9,        1,   152064, 66f0368b106e9c32cca7fa328cca833f
> +0,         10,         10,        1,   152064, 092ec763ee4fd5e160fd66891baa9f0f
> +0,         11,         11,        1,   152064, 1b1f70815e3554088da4797fd7e044f2
> +0,         12,         12,        1,   152064, 0754cf3a6eb98b585e302be006288064
> +0,         13,         13,        1,   152064, 5692f89e7a8f9b03311a664c0dc212a8
> +0,         14,         14,        1,   152064, 589de0dc2fdef4914f53e4be5900d2a8
> +0,         15,         15,        1,   152064, 992476c60d387ce7717a627ce8d40edd
> +0,         16,         16,        1,   152064, 72e4135ac776ed19ce2f07183bba34cb
> +0,         17,         17,        1,   152064, c93d2e298b597f0d0e91f8960c1c4588
> +0,         18,         18,        1,   152064, ff5bfc1fc0248d9f22fac3b2c3339f02
> +0,         19,         19,        1,   152064, 2c2e80f377b58a5ae1887297830a0c50
> +0,         20,         20,        1,   152064, fe7579b65f02835d12b7a75c7b8d9346
> +0,         21,         21,        1,   152064, 68e21ff75484658a0728a61ea0379672
> +0,         22,         22,        1,   152064, adf6224c4a110ce86f5d87d661bb86dd
> +0,         23,         23,        1,   152064, 91d5ed4e2aa61c0ac2ff7989712459be
> +0,         24,         24,        1,   152064, 37faefac606e73aea42f30a933e036de

what is causing this change ?
has this been checked to be ok ? / correct ? / benign ?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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