[gst-devel] Using gnonlin to extract time segments from a video file

[Rodrigo Manhães]

Hi,

First of all, thanks for the replies!

I applied your instructions about the properties to some examples
found on Internet, but didn't work. So, I created a video pipeline by
myself and I'm facing problems on linking dynamic pads from
gnlfilesource to both video and audio streams. As of GStreamer
Documentation, decodebin emits one "new-decoded-pad" signal for each
decoded stream. Neither gnlcomposition nor gnlfilesource accept a
new-decoded-pad signal. How can I register a callback for these
signals?

[]'s
Rodrigo


2009/2/10 Edward Hervey <bilboed at gmail.com>:
> Hi,
>
>  For your use case apply the following properties if you want to cut D
> seconds starting from A:
>  # outside time-realm (what it will output)
>  gnlsource.props.start = 0 # the output starts from 0 ...
>  gnlsource.props.duration = D # ... and lasts D nanoseconds
>  # inner time-realm (what you are extracting)
>  gnlsource.props.media_start = A
>  gnlsource.props.media_duration = D
>
>  One thing to take into account is that gnlfilesource will decode the
> contents to raw audio/video (because it uses decodebin(2)). That means
> you'll need encoders and muxer after your compositions.
>
>  As a side note, but I'm not sure whether you'll encounter this with
> such a simple use-case, gnlfilesource has a few issues due to the queues
> it uses internally. If you see the resulting file stopping before the
> end, you will have to use a queue-less bin within a regular gnlsource.
>  Since you're using python you can re-use such an element I created in
> PiTiVi : SingleDecodeBin (git.pitivi.org ,
> pitivi/elements/singledecodebin.py) and put that in a regular
> 'gnlsource' along with the above properties.
>
>  I hope this helps.
>
>    Edward
>
> On Tue, 2009-02-10 at 01:32 -0200, Rodrigo Manhães wrote:
>> Hi,
>>
>> I need to build a small command-line tool for extracting a time
>> segment from a video file, creating another video file as result
>> containing the desired segment. I've tried to do this creating a
>> pipeline whose source is a gnlfilesource and the sink is a filesink
>> and limiting the playback to the desired timebox.
>>
>> I got good results on this same goal for audio files. For video files,
>> however, the gnlfilesource's properties for start and duration are
>> ignored. Has gnonlin some limitation in this sense or the problem is
>> in my code?
>>
>> I've tried to do the same thing with gstreamer without gnonlin and
>> didn't get success.
>>
>> The language I'm using is Python.
>>
>> I thank any help or link for information.
>>
>> []'s
>> Rodrigo
>>
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>
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