[FFmpeg-devel] [PATCH] asf muxer: gracefully handle negative timestamps

[Michael Niedermayer]

On Thu, Mar 11, 2010 at 12:37:20PM +0100, Vladimir Pantelic wrote:
> Michael Niedermayer wrote:
>> On Thu, Mar 11, 2010 at 12:15:16PM +0100, Vladimir Pantelic wrote:
>>>  I have one asf file that when remuxed to asf with vcodec/acodec copy for
>>>  some reason has negative dts.
>>>
>>>  These negative dts end up in "sendtime" as a large integer, putting the
>>>  send
>>>  time in future of the payload presentation time. This is due to the fact
>>>  that (int)asf->packet_timestamp_start is converted to (unsigned
>>>  int)sendtime
>>>
>>>  Attached patch make sure that we write a sendtime of 0 in this case.
>>>
>>>  This fixes some complaints that M$ "Windows Media ASF View 9 Series" has
>>>  with the generated file.
>>
>>>   asfenc.c |    4 ++--
>>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>>  5a18e0df6769452b2874689888dfdd832cca85dc  asf_fix_send_time.patch
>>>  Index: libavformat/asfenc.c
>>>  ===================================================================
>>>  --- libavformat/asfenc.c	(revision 22465)
>>>  +++ libavformat/asfenc.c	(working copy)
>>>  @@ -585,7 +624,7 @@
>>>
>>>   static int put_payload_parsing_info(
>>>                                   AVFormatContext *s,
>>>  -                                unsigned int    sendtime,
>>>  +                                int             sendtime,
>>>                                   unsigned int    duration,
>>>                                   int             nb_payloads,
>>>                                   int             padsize
>>>  @@ -626,7 +665,7 @@
>>>       if (iLengthTypeFlags&  ASF_PPI_FLAG_PADDING_LENGTH_FIELD_IS_BYTE)
>>>           put_byte(pb, padsize - 1);
>>>
>>>  -    put_le32(pb, sendtime);
>>>  +    put_le32(pb, FFMAX(0, sendtime));
>>
>> muxers are not supposed to store random values
>>
>> id suggest
>> 1. add a flag to muxers specifying the capability of negative dts support
>
> add AVFMT_POSITIVE_TIMESTAMPS to asfenc, or AVFMT_NEGATIVE_TIMESTAMPS
> to all others?

AVFMT_POSITIVE_TIMESTAMPS, id say


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

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20100311/17ad4a0b/attachment.pgp>