29 replies to this topic

[kurben]

Is there some way to change the audio and video buffer size in Enigma2 ?
It is the dvb live tv buffers that I would like to edit not the Gstreamer buffers.
Is it even possible? Or is it completly hardware/driver based?

The reason I would like to edit this is because I think this could perhaps solve my audio dropouts on channels with aac-he audio.

[littlesat]

You can initiate an additional buffer with the last digit in the service reference... This by changing the last digit usual 0 into 1 (RAM only) or 3 (also via HDD).

Edited by littlesat, 29 November 2015 - 15:25.

[Erik Slagter]

You can initiate an additional buffer with the last digit in the service reference... This by changing the last digit usual 0 into 1 (RAM only) or 3 (also via HDD).

That is gstreamer. TS requests DVB.

 

Yes it is possible. No it won't fix your problems. The buffers are already huge, multiple megabytes. The decoder only starts running when enough data has been received to play smoothly. If you get hiccups, the stream is already broken (timestamps, vbv, etc) or the driver is buggy. What receiver?

[kurben]

Vu+ SoloSE v2 with DVB-T2 tuner.

 

The problem is only on channels with AAC-HE audio. If the channel has dual audio with AC3 and AAC-HE, the AC3 stream is perfect. 

I have reported this to VU+ but nothing happens. 

 

Same problem as this guy haves: http://www.world-of-...strial-T2-tuner

 

When streaming from the VU+ to Kodi the audio is better but not perfect as the AC3 stream is.

 

I have tried every downmix setting possible but to no avail.

 

Same problem on all images, Vu+ original, OpenPli, Openvix, Black Hole, open black hole etc...

 

I think it is related to either Vu+ drivers or Enigma2 code base?

 

The audio is perfect if I use the inbuilt tuner in my Panasonic TV so it is not related to reception, I have 98% on both signal and quality.

[MiLo]

What is the SOURCE of the data? (DVB? File? Network?)

[kurben]

DVB-T2 channel Live tv, Video HD 720p h.264 Audio AAC-HE.

[MiLo]

Live TV does not pass through any buffers. It's all hardware routing, no buffering involved.

(If you shoot down E2 using kill -9 or so, TV will just keep on playing)

Edited by MiLo, 30 November 2015 - 12:00.

[kurben]

I have also tried with a USB DVB-T2 tuner (Hauppauge PCTV NanoStick T2 HD 290e) and the same audio problem occurs on that one. But only on the Vu+ box. Not if I use the usb tuner on my Openelec mediapc or Windows laptop.

[Erik Slagter]

Live TV does not pass through any buffers. It's all hardware routing, no buffering involved.

(If you shoot down E2 using kill -9 or so, TV will just keep on playing)

You'd probably have to STOP enigma instead, because otherwise the fd's get closed and the hardware stops

[kurben]

I tried some other things this week.

 

If I record a channel with AAC-HE and play back the file on my PC or mediacenter, the sound is at the right level and without audio dropouts.

 

If I play back the recorded file using Mediaplayer 1 or 2 on the Vu+ SoloSE using G-streamer the audio is STILL to low and with audio dropouts!

 

So where lies the problem? Is it related to Enigma2 or Vu+ hardware?

[Erik Slagter]

Or... drivers.

 

Try it with the driver update from yesterday (just updating should be enough).

[kurben]

I tried it yesterday and no difference when updating.

 

I discovered another strange thing instead. I found a channel on another mux with video h.264 but with SD (720x576i) and with AAC-HE audio. On that channel the audio is perfect and with correct level??? 

 

When I found this out I discovered that the Audio problem regarding AAC-HE is only related to HD channels! I tried several other channels and for the time it seems like the only option?

 

And also, why the hell does the problem still exist when watching recorded programs? Isn't it supposed to use G-streamer when playing back recordings?

[Erik Slagter]

I've seen it too using vtuner. It's better/worse depending on the channel, there is no real systematic.

[kurben]

Then it is not the drivers for the Vu+ tuner. Since I get the same audio problem even if using a USB DVB-T2 tuner on the VU+ box.

 

What is vtuner? and who is writing that part? Vu+ or other?

[Erik Slagter]

VTuner = virtual tuner. And yes, exactly an USB tuner makes use of that...

[betacentauri]

Playback of normal recordings don't use gstreamer. Gstreamer is used for mkv, avi, MP3, flac and so on. So not for a DVB recordings (if they have a .ts extension).

[kurben]

OK. I tried and recorded a channel with audio problems on AAC-HE and converted the file to a mp4 file without transcoding. Left the audio untuched.
When playing back the mp4 file the audio was perfect. Playing back the untouched ts file showed the same audio problem as usual.

So the bug is only related to ts and dvb playback.

Can some one give me any hint on how I can trace where the bug is?

[Erik Slagter]

From this experiment it is very clear where the cause can be found...

[Dambedei]

Would it be possible to add a tiny buffer for (network)-TS-Streams?

My box doesn't have a tuner connected so i need Fallbacktuner/remotechannelconverter.

I have tested streaming with dreambox8000/800SE and Maxdigital XP1000.

Dreambox 8000 and XP1000 suffer from audio drops after switching channels till it finally normalizes and playback is perfectly fine.

Dreambox 800se never has audio drops but stops playback for about 1 second and then plays smoothly.

 

So basically it looks like the client/server needs to "catch up" and then it works flawless, would a buffer help here?

Edited by Dambedei, 8 December 2015 - 13:22.

[Erik Slagter]

The problem probably exactly that is what happening. The DVB hardware wants to fill a buffer, but it only gets the stream at "play" rate, at a little delay from earlier buffering. The solution should be sought somewhere else, the stream should be "corked" for a little while before the decoder starts playing. But I am not sure if that's possible.