[linuxtv-softmpeg] Re: Improvements in EPIA-M softdevice?

[<ac2crp@blueyonder.co.uk>]

Hi,

> It worked just fine over night.

That's really cool! More than I've been able to get it to do ! :-(

> OSD started flickering at
some point, though.. Weird effect. Looked like OSD toggled on/off several
times per second, at random spot because there were visible "stripes"
where OSD appeared or disappeared during screen refresh..

Hmmm. I wonder if that's something to do with the double buffering of the framebuffer and video. That stuff is all handled by DirectFB - and the chip does the alpha blending between the video and framebuffer. Hmmm....

> Then there was quite a lot of mpeg bugs in some channels, but I think that
it might be the DVB-T card overheating or something?

Did it survive even with the MPEG bugs? I put in some debug - like 'VIDEO BUFFER FULL' and stuff - that shows conditions where the normal softmpeg code would have segfaulted. If it survives those... even better!

> I've thought further about the frame skip problem. It seems to skip
almost exactly two times per second. Most DVB streams have I-frames as
every 12th frame... Is it possible that there is some bug that I-frames
are not displayed?

The d_cle266.c file is something that I'm not proud of :-( I agree that the problem occurs only during I frames.

libsoftmpeg passes a whole frame's worth of video to the decoder. However, the parser that I'm using looks for the next frame start code. It therefore doesn't return 'ready' indicating a complete decoded frame until it receives the next frame's start code. libsoftmpeg also needs to know when a frame is an I frame in order to get correct AV sync. The code I put in to detect this is extremely un-nice. I (foolishly) wrote some rather rough code quickly in order to test that the decoder would vaguely work, with the intention of tidying it up in order to be incorporated with libsoftmpeg properly later. However, I got bogged down trying to find out why my code segfaulted so often. I might try deleting the installed DirectFB and fusion sound etc in case I have some header mismatch. I thought I'd tried that, but I perhaps haven't recompiled everything.

It's good that it's progressing though!

I've copied this mail to the libsoftmpeg mailing list in case anyone else is interested.

Let me know how you get on. I'll try reinstalling everything on mine and see if I have any luck.

Thanks,

Colin


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