GSoC 2017: Delays in code cleanup

This week the some of the issues from last time were fixed, some are still under work and some new ones surfaced. Julien has been busy this week and has been unable to provide much input which slowed down some work. I’ll discuss this week’s developments in brief below.

Seeking issue (mostly) fixed

The most important issue form last week was seeking fail. After some digging I found that it was simply because the output buffer was reset before being cleared in “reset_streams_parameters” when the output port was disabled. Simply removing the line that resets the buffer fixed the crash that happened while seeking. The only little problem left is that now the decoder spawns lots of errors similar to this in terminal when trying to seek.


This however does not affect the video playback. The same behaviour is also seen with the existing bellagio based OMX IL state tracker. Being a joint problem with gst it shouldn’t be a blocking the project.

Overriding input port SetParameter

The first go we had was on #2 . Though the exact reason not yet known, the issue could be related to dropped buffers so we decided to override the component’s SetParameter. In bellagio you can simply replace component’s pointer for the SetParameter function like this example from h264enc.c

comp->SetParameter = vid_enc_SetParameter;

In tizonia, to do so you need to add a separate port with it’s SetParameter function overridden with the custom version. The full commit can be found here.

Though this change didn’t fix the issue, it would be good in general such as avoiding unnecessary reconfiguration when there is no resolution change. Since this is an advanced feature it shouldn’t block the decoder patches from getting reviewed.

Encoder crash

Previously I assumend that the crash in the encoder was related to the changes I made recently. After some digging and checking I found that the commits that used to work earlier have stopped working with the same error. So this error might be due to external factors like Gstreamer. We are still waiting to find a fix after the decoder is done.

Preparing commits

Originally the plan was to get the decoder reviewed soon. The first task was to rebase the branch on the latest mesa master branch and resolve the conflicts. The result after resolving conflicts can be found on the gsoc-rebase branch which is separate from gsoc-dev to validate the rebase. It configures successfully but fails to compile. The related issue can be found here. After this hopefully the decoder will be ready for review.

Up next

Since the project end period is looming near the priority is to get the decoder and the encoder reviewed as soon as possible. The issues still present and the new ones that surfaced are slowing down this process. The next few weeks will surely require some hard work.


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