[vlc-devel] Updated patch for ogg/theora seeking

salsaman salsaman at gmail.com
Wed Jun 9 19:35:45 CEST 2010


As a result of my work, I would like to propose a new flag for the stream:

STREAM_CAN_EXACTSEEK

- the proposed meaning of this flag is that within the stream one can seek
exactly to any given frame without artifacts in the frame. This flag must be
settable by the demuxer plugin, and is not fixed - for example you could
have a container with two video streams one after the other, the first could
set this flag and the second (using a different codec) could be not
seekable.

Rationale:
I understand that you are creating libvlc with the intention of this being
used for video editing applications. I know from my own experience with
LiVES that such applications require demuxers which can deliver the exact
frame requested, so generally one would need to look at STREAM_CAN_EXACTSEEK
| STREAM_CAN_FASTSEEK to see if the stream is immediately usable or requires
further processing (caching, indexing, etc).



Regards,
Gabriel.





http://lives.sourceforge.net
https://www.ohloh.net/accounts/salsaman



On Wed, Jun 9, 2010 at 10:37 AM, salsaman <salsaman at gmail.com> wrote:

> You could also try uncommenting some of the fprintf in oggseek.c and seeing
> what happens.
>
> You should see it homing in on the keyframe before the target frame.
>
>
> Gabriel.
>
>
> http://lives.sourceforge.net
> https://www.ohloh.net/accounts/salsaman
>
>
>
> On Wed, Jun 9, 2010 at 10:19 AM, salsaman <salsaman at gmail.com> wrote:
>
>> OK, here is the patch updated with FASTSEEK.
>>
>> If you are seeing problems even after downloading elephants dream, then I
>> think there is some other problem. Maybe you are using a different demuxer
>> (avformat ?) instead of the ogg demuxer ?
>>
>>
>>
>> Regards,
>> Gabriel.
>>
>> http://lives.sourceforge.net
>> https://www.ohloh.net/accounts/salsaman
>>
>>
>>
>> On Wed, Jun 9, 2010 at 3:52 AM, Ilkka Ollakka <ileoo at videolan.org> wrote:
>>
>>> On Tue, Jun 08, 2010 at 07:28:27PM -0300, salsaman wrote:
>>> >    Please check back in this thread. I asked how to tell if we are
>>> dealing
>>> >    with a stream or a file, and I was told to use stream_Control(
>>> stream_t *,
>>> >    STREAM_CAN_SEEK, &boolean );
>>>
>>> Hi,
>>>
>>> You don't really need to know if access has file or stream coming in do
>>> you? Seems that you just need to know if it can be seeked (fast in this
>>> case seems like the info you need ) so STREAM_CAN_FASTSEEK would tell you
>>> if
>>> seeking is really a fast one (like local files etc) or not (not able to
>>> seek, or slow seek like in http-case).
>>>
>>> I think there could be still seeking problem even with local files. I
>>> tried that elephantsdream as local file, and it behaved same as behind
>>> http, so maybe patch is missing some boundary limit, or I just had some
>>> other problem in that case. I'll try to test more tonight.
>>>
>>> --
>>> Ilkka Ollakka
>>> "I've seen, I SAY, I've seen better heads on a mug of beer"
>>>                -- Senator Claghorn
>>>
>>> _______________________________________________
>>> vlc-devel mailing list
>>> To unsubscribe or modify your subscription options:
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>>>
>>>
>>
>
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