bug: video artifacts on multiple instances of codec use on AMD Radeon

[Papou]

Ever since I use Avidemux3 QT (2.8 now) with Xvideo on Ubuntu 12.04, I may get corrupted video display.
HW is TK11-BZ-015BE 16GB AMD combo: E450 2Ãâ€"1.65MHz + Radeon HD6326 256MB
It happens in any video mode (X11, Xvideo, VDPAU, OpenGL).
See workaround at the end of this description.

I have finally found the circumstances...
It happens when another program, started first, including another instance of Avidemux itself, uses an AVC codec, be it the system's codec or the codec bundled in Avidemux.
The bug can be demonstrated as simply as having such a started first program paused in the background and Avidemux frame stepping with the right/left arrow key.
One or several stripes like in the attached picture occur say every 20 frames.
Horizontal blocks of the same window are repeated randomly (a replay is different).
For example, the bottom 1.5 cm of the image is repeated in its middle.
Hiding and uncovering the window randomly produces a correct or identically striped picture.

The rest of the Ubuntu system is working perfectly, esp. multiple instances of system's video codec.

Another artifact occurs when the frame sizes are not multiple of 8.  See sloping stripes in second picture.
A possible hint toward locating the problem is that, in a secondl instance, this second, sloping artifact does not occur although the first artifact does.
To me, it looks like a misunderstanding between the Avidemux embedded codec and the video driver or Avidemux.

With VDPAU (used only as an informative test), a SINGLE Avidemux instance exhibits the problem !!!
After this, a SINGLE X11, VDPAU or OpenGL Avidemux instance exhibits the problem too.
Xvideo has to be configured again to return to normal operation.

I have finally found a workaround for both artifacts. That's configuring
Editer>Preferences>Display> both Activer OpenGL and Affichage vidéo: OpenGL

If the whole of the system is perfect and Avidemux 2.5 is alright in ALL video modes and Avidemux 2.6 produce these artifacts in ALL video mode, I think I have demonstrated a PROBLEM somewhere in the code that's common to all modes but that is bypassed when the OpenGL option is used.

Hoping this can help.
Thanks. Cheers.

[Papou]

I reopened this fresh thread because two blokes messed up a former one, saying for example that my CPU is not fast enough, to which I replied that it's fast enough for frame stepping, that I am editing two videos simultaneously, to which I replied that I don't, just checking that Avidemux can read what it just encoded, that I'm watching video with Avidemux, not true, that I should use 2 computers, that Avidemux cannot run multiple instances, etc.
And they said that I don't accept plausible causes, that I am a bad guy because I suspect a bug and even that I came here looking for a fight !!!
My God!  For heaven's sake, thank you for trying to help but please don't come back.
I'm just trying to get Avidemux better as much for everybody as for myself.

[Jan Gruuthuse]

VDPAU only supported on nvidia cards supporting VDPAU, don't use this. Don't use 2 instances of avidemux. Keep on dreaming!

A new thread and already picking a fight again: good luck. I leave you to it!

One of the two blokes

[AQUAR]

Guess I probably am the other.
Move to Sorrenson Squeeze - then we will all be very happy!

Pity some people come to this forum just to argue with those trying to help with issues.
We are not perfect with our advice, that is for sure, but hey at least we try.

Lets see how many here are willing to respond to this inconsequential rendering flaw, especially after
that kind of derogative intro about people that gave you their time and effort.
Let me give you the advice you gave us "go away".

The above are purely my opinion and they in no way represent those of other members here.
They can speak for themselves - and some may be on your side - so they can help you out (can't they!).

I'll just make this my final comment on this topic - the issue does not exist on any of my PC's.

[mean]

You are using VDPAU with ati cards
It might be  a bug in the vdpau driver or it does not behave like the nividia one

[Papou]

Merci.
No, I'm using Xvideo (http://www.avidemux.org/smf/index.php/topic,13406) with which all that I describe happens.
I just tested all 4 in hope to shed  some light.
And I think it does: VDPAU needs only 1 instance to meet the problem AND it is sticky: after that the others only need one instance too.

[Papou]

I have found how to work around both artifacts. That's configuring
Editer>Preferences>Display> both Activer OpenGL and Affichage vidéo: OpenGL
Everything is now normal, meaning great!
Hoping this can help. Thanks for trying.

Now I expect apologies for having been rudely accused of "picking a fight" and refusing probable solutions when gently replying that suggested actions did not work or do not apply.   I'm particularly happy to have "fought against" buying a second computer.

Note 3 missing accents:  Éditer>Préférences>

[Jan Gruuthuse]

Now I expect apologies for having been rudely accused of "picking a fight" and refusing probable solutions when gently replying that suggested actions did not work or do not apply.   I'm particularly happy to have "fought against" buying a second computer.

Certainly not! No apologies from me, I don't see why I should.

vdpau only works with some nvidia GPU
opengl if vdpau not possible
xvideo if none of above works
x11 is only last resort if nothing else works

Certainly don't mix opengl with vdpau.

I mostly am here not to get help indeed but to report an issue that will help making a better avidemux for everybody and the least that can be said is that your calling that picking a fight is highly appropriate.

[Papou]

vdpau only works with some nvidia GPU
opengl if vdpau not possible
xvideo if none of above works
x11 is only last resort if nothing else works

Certainly don't mix opengl with vdpau.

Why this always repeated VDPAU?  Simple...

What is the display driver ? Xv ?

Avidemux QT (2.6.7 now), Driver is Xvideo.
But it happens with any video driver (X11, Xvideo, VDPAU, OpenGL)

You are using VDPAU with ati cards

No, I'm using Xvideo (http://www.avidemux.org/smf/index.php/topic,13406) with which all that I describe happens.
I just tested all 4 in hope to shed  some light.

I have found how to work around both artifacts. That's configuring
Editer>Preferences>Display> both Activer OpenGL and Affichage vidéo: OpenGL

I NEVER used VDPAU.
I was using Xvideo which, just as the other drivers, does not work well and now I'm using OpenGL which works well, but only with the OpenGL option set.

[Jan Gruuthuse]

Why this always repeated VDPAU?  Simple...

What is the display driver ? Xv ?

Avidemux QT (2.6.7 now), Driver is Xvideo.
But it happens with any video driver (X11, Xvideo, VDPAU, OpenGL) *1

You are using VDPAU with ati cards

No, I'm using Xvideo (http://www.avidemux.org/smf/index.php/topic,13406) with which all that I describe happens.
I just tested all 4 in hope to shed  some light.*1

I have found how to work around both artifacts. That's configuring
Editer>Preferences>Display> both Activer OpenGL and Affichage vidéo: OpenGL

I NEVER used VDPAU. *2
I was using Xvideo which, just as the other drivers, does not work well and now I'm using OpenGL which works well, but only with the OpenGL option set.

VDPAU is an option/setting in avidemux that is why it returns everytime.
You claim you used/tested vdpau *1
Now you claim you never used it  *2
Why that focus on VDPAU, you did not read the rest of advice?
- vdpau only works with some nvidia GPU
- opengl if vdpau not possible