[FFmpeg-devel] Corrupt duration in packet while encoding to WMA

Ronen Mizrahi ronen
Tue Dec 4 00:18:07 CET 2007

Michael Niedermayer wrote:
> On Mon, Dec 03, 2007 at 01:56:56AM -0500, Ronen Mizrahi wrote:
>> Hello,
>> While using ffmpeg to encode to WMA we noticed that when the call below
>> is made in asf-enc.c, packet_timestamp_end is smaller than
>> packet_timestamp_start and hence a negative duration is written to the
>> packet. While Windows Media Player did not seem to care about it,
>> Windows Media Player CE (the one used in Pocket PC and Windows Mobile)
>> exhibited an odd behavior (such as skipping several seconds slightly
>> after starting playback). Changing the order between the start and the
>> end below, seems to fix the problem, however I am not certain it is the
>> correct thing to do, and would very much appreciate some feedback from
>> the maintainer of asf-enc.c
>> This is the call where we believe there is a bug:
>> put_payload_parsing_info(
>>                             s,
>>                             asf->packet_timestamp_start,
>>                             asf->packet_timestamp_end -
>> asf->packet_timestamp_start,
>>                             asf->packet_nb_payloads,
>>                             asf->packet_size_left
>>                         );
> thanks for the info
> i think ive fixed it in svn, please check!
> [...]
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Thank you I did check it and it seems to do the trick. There are still
cases where the end is equal to the start but I suspect these are valid
Playback of WMA encoded via ffmpeg over HTTP with Windows Media Player
CE 1.0 is much better although still not perfect.

Thank you for fixing it.


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