On 02/16/2017 10:19 AM, Vittorio Giovara wrote:
> On Thu, Feb 16, 2017 at 11:14 AM, John Stebbins <[email protected]> 
> wrote:
>> On 02/15/2017 10:09 PM, Luca Barbato wrote:
>>> On 15/02/2017 23:29, John Stebbins wrote:
>>>> ts_offset was added to cluster timecode, but then effectively subtracted
>>>> back off the block timecode
>>>> ---
>>>>  libavformat/matroskaenc.c | 1 +
>>>>  1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
>>>> index e951a0f..2fe6e0e 100644
>>>> --- a/libavformat/matroskaenc.c
>>>> +++ b/libavformat/matroskaenc.c
>>>> @@ -1461,6 +1461,7 @@ static void mkv_write_block(AVFormatContext *s, 
>>>> AVIOContext *pb,
>>>>      uint8_t *data = NULL;
>>>>      int offset = 0, size = pkt->size;
>>>>      int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : 
>>>> pkt->pts;
>>>> +    ts += mkv->tracks[pkt->stream_index].ts_offset;
>>>>
>>>>      av_log(s, AV_LOG_DEBUG, "Writing block at offset %" PRIu64 ", size 
>>>> %d, "
>>>>             "pts %" PRId64 ", dts %" PRId64 ", duration %" PRId64 ", flags 
>>>> %d\n",
>>>>
>>> What does it fix? should it go in stable?
>>>
>>>
>> When setting initial_padding for an audio stream, the timestamps are written 
>> incorrectly to the mkv file.
>> cluster timecode gets written as pts0 + ts_offset which is correct, but then 
>> block timecode gets written as
>> pts - cluster timecode which expanded is pts - (pts0 + ts_offset) .  Adding 
>> cluster and block tc back together
>> cluster tc + block tc = (pts0 + ts_offset) + (pts - (pts0 + ts_offset)) = pts
>> But the result should be pts + ts_offset since demux will subtract the 
>> CodecDelay element from pts
>> and set initial_padding to CodecDelay. This patch gives the correct result.
> Bonus points if this comment is added verbatim to the commit log.

Done

-- 
John      GnuPG fingerprint: D0EC B3DB C372 D1F1 0B01  83F0 49F1 D7B2 60D4 D0F7


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