Synchronising audio and video in gnonlin

[Ralph]

> I don't know how your pipeline is
> Basically I did 2 gnlcomposition, one for audio and another for video.

As I wrote in the beggining of my original post, my pipeline contains two
separate gnlcomposition objects: one for audio and the other for video.
The whole pipeline looks like that:

videotestsrc - gnlsource     \
                gnlfilesource     - gnlcomposition - d3dvideosink
                gnlfilesource  /

audiotestsrc - gnlsource     \
                gnlfilesource     - gnlcomposition - audioconvert -
audioresample - autoaudiosink
                gnlfilesource  /

The sources (audiotestsrc, videotestsrc, gnlsource, gnlfilesource) are not
explicitly added to the pipeline, they are added to gnlcomposition objects.


> I achieved this by the caps properties

As the avi files contain both audio and video, I need to filter the pads of
gnlfilesources, I'm setting their caps to "audio/x-raw-int;
audio/x-raw-float" for audio sources or "video/x-raw-rgb; video/x-raw-yuv"
for video sources.  This gnlcomposition objects forward those caps to the
remaining part of the pipeline.

I noticed a queue object in the video pipeline in one of your messages, I
tried adding it, but it didn't make any change.



Rossana Guerra wrote
> 
> I don't know how your pipeline is, but when I did crossfading I achieved
> this by the caps properties. Even it fits for 2 video files I think the
> principle is the same.
> Here's the thread:
> 
> http://gstreamer-devel.966125.n4.nabble.com/crossfading-audio-error-gst-mad-chain-mad-header-decode-had-an-error-lost-synchronization-td4037851.html#a4037881
> 
> Basically I did 2 gnlcomposition, one for audio and another for video.
> Sorry I don't have the pipeline in this computer.
> But it was something like this.
> 
> http://gstreamer-devel.966125.n4.nabble.com/No-sound-in-my-pipeline-td3854506.html
> 
> Hope it helps.
> Rossana
> 
> 2012/1/17 Ralph <ralph.gucwa at .co>
> 
>> I'm using gnonlin to play a sequence of video file fragments. I
>> constructed a
>> pipeline containing two gnlcomposition objects - one for video and the
>> other
>> for audio, they are playing the same video files. In order to be able to
>> have gaps between the files, I created videotestsrc and audiotestsrc and
>> added them through gnlsources (priority: uint.MaxValue) to gnlcomposition
>> objects.
>>
>> My "timeline" looks like this:
>> 659.24s file, start position 2s (2s gap before the file)
>> 881.04s file, start position 661.24s (4s gap before the file)
>>
>> When I disable the audio part, the video works nicely - the file
>> fragments
>> are played exactly when scheduled and the gaps between them are precisely
>> the required length.  Perfect!  The problems occur when I enable the
>> audio
>> section - the gaps become much shorter, strange things start to happen.
>>
>> When I try to play both video and audio, the first file begins after just
>> 0.4s, and when it ends, the video skips the second gap and jumps many
>> seconds into the second file and the video remains frozen, it waits for
>> the
>> audio (which is playing nicely except for the 1.6 second shorter gap) to
>> that position and then continues.
>> What's interesting the length of the initial gap is always 1.6 seconds
>> shorter than it should be - when the gap should be 20s, it is played
>> within
>> 18.4 seconds.  The second gap is always completely wrong.
>> It's not the problem with the video, if I disable the video section, the
>> audio is wrong, the gaps are shorter than scheduled.
>> What's wrong with my pipeline?
>>
>> My video files are:
>> video: Xvid ISO MPEG-4 720x576 25fps
>> audio: MPEG-1 Layer 2 48kHz 192kb/s stereo
>>
>> The audio gnlcomposition runs at 48kHz, the audio is then converted using
>> audioconvert.
>> The audiotestsrc runs at 44.1kHz.
>> The autoaudiosink runs at 44.1kHz.
>>
>>
>> --
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