[gst-devel] muxers, timestamps, sparse and continuous recordings

[sudarshan bisht]

Hi ,
       I had also tried this thing , I was getting same video frames for
the particular duration . Its not a problem of muxers i guess  . Because
muxer creates its own timestamp and attach it to the buffer . Its problem of
tea element where you connect your preview and record pipeline  . Whenever
you add a new pipeline to the running pipeline so what I think is all the
elements of second pipelines should be  in sync with the existing pipeline
because source element is common here .  So in order to do that tea element
keep pushes same video frame for that particular duration that is same as
the time till you press record.  To fix this problem what I did is wrote a
plugin which sends running pipeline's position as a timestamp for the first
buffer , only for the very first time . And I insert this plugin right after
tea element in record pipeline.

 This has fixed my problem .


On Thu, Sep 11, 2008 at 6:50 AM, Eric Zhang <nicolas.m.zhang at gmail.com>wrote:

> Hi, Stefan:
>
>     I think your pipeline is using GstSystemClock because you mentioned the
> source is a live element. If it is, the clock will keep increasing even if
> the pipeline is paused. This makes the timestamp noncontinuous. To generate
> a continuous timestamp, I think you can try to use the clock provided by
> your sink elements. Maybe this is not easy because the live element is
> different with other source elements.
>
> Eric
>
> 2008/9/10 Stefan Kost <ensonic at hora-obscura.de>
>
> hi,
>>
>> i was wondering how muxers should handle timestamps on incoming buffers.
>> Assume an applications that shows video from a camera. When you click a
>> button it records to file, allowing to pause and unpause in between. The
>> recorded file should have a continuous stream. If I don't do any special
>> casing this is not the case.
>>
>> 1) When I playback the recorded file, I have an initial pause before
>> video start (if I pressed record after two seconds, the video will start
>> after two seconds).
>>
>> 2) If I pause in between, also in the playback there is a pause.
>>
>> Right now I work around with a pad probe that looks at disconts to
>> aggregate a time_stamp_offset and correct all incoming buffers by
>> subtracting that. It works but probably is not the right way. I believe
>> this involves the use of segments, but I am not sure how. Also both
>> behaviors might be valid (having a sparse and having a continuous
>> stream). So the application would somehow be involved to select the
>> desired behavior. Any comments?
>>
>>
>> Stefan
>>
>>
>>
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-- 
Regards,

Sudarshan Bisht
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