Video dont play since 5.1.4

[biotec]

Hello,

After upgrading to VirtualBox 5.1.4, video don't play back correctly using mplayer, vlc, or trying to whatch youtube videos from a browser.
The trouble persist on version 5.1.6 and on the test build 5.1.7-111038, in all case I have installed the correspondig extensions ang guest additions.

Symtoms with mplayer is that video playback freezes after a few frames or it runs very slow with bad sound. It down not seem to depend on video format. With vlc, we can play the video, but without any sound, and it gives the following error message:

alsa audio output error: cannot estimate delay: Input/output error

My host is a i5 running Slackware 14.2 (64-bit version).
The guest is a derivative of Slackware 14.2 too. The same behaviour is observed using a 32-bit guest and a 64-bit guest.

Reverting to 5.1.2 or earler "solves" the problem. I am using virtualbox with the a similar setup since 5 or 6 years already on a dayly base and this trouble is new to me.

Could anyone give me a clue who to solve, please? Am I the only to have this trouble?

[mpack]

Please post a VM log file. With the VM fully shut down, right click it in GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

[biotec]

Hello, thanks for helping.
Here is the log after running a 32-bit guest on virtualbox 5.1.6.

[mpack]

? I don't find any evidence that 3D acceleration is enabled, hence the guest will be doing software rendering of video, hence any problem you have playing videos has nothing to do with VirtualBox.

I also notice that you chose "Linux 2.6" as the template. If this is based on Slackware 14.2 then it has a 4.x kernel.

Also this :-

00:00:00.480668 Host RAM: 3843MB total, 2829MB available
...
00:00:00.604722 RamSize <integer> = 0x0000000080000000 (2 147 483 648, 2 048 MB)
00:00:00.605188 VRamSize <integer> = 0x0000000004000000 (67 108 864, 64 MB)

You are uncomfortably close to consuming all of the available RAM on your host. I think you should reduce the RAM allocation to 1024MB. You can leave graphics RAM where it is.

In a similar vein you have assigned two cores to the guest, from a host CPU that only has two cores total. This can cause problems. Yes, you have hyperthreads, no they don't count.

Finally I would note that Slackware is not an officially supported host as far as I can tell.

[biotec]

Hello,

first of all, thanks for your help.

However, the things you pointer do not seem to be related with the present problem, and changing them did no help:

(1) Activating 3D acceleration has had no visible effect.

(2) What you call "Linux 2.6" template is reported on the virtualbox configuration manu as "Linux 2.6/3.x/4.x", which fits my needs. However, just in case, I tried "Other Linux" and "Arch" with the same bad results.

(3) Reducing RAM to 1G instead of 2GB had no effect either. Besides, the trouble is not related to the load of the system because I tried with both the host and the guest with a low RAM load (checked with free). No noticeable slowndown was observed on other tasks.

(4) I assigned two cores, and my system has 4 cores, not 2. But just in case, I tried with just one, and the trouble continues unchanged.

(5) Doing all mods above one by one was unsuccessful, as they are equally useless all together.

(6) Slackware may be not officially supported, but you may know that it is a fairly standard and plain system that never had shown incompatibilities with virtualbox. Also I tried using several recent kernels (4.4.22, 4.7.5 and 4.8.1), and the trouble remained unchanged.

Finally, I may add some new informations about that trouble. I am now almost certain it is only related to sound. Video slowndown or freeze is only present when sound fails. I managed to make sound to work after playing a sound file with aplay. Then, mplayer works well (sound and video) just for one single run; the following runs are then again faulty, until I play a sound with aplay again, and so on. I still ignore who is the culpitr because this does not happen on virtualbox 5.1.2 or earlier.

Maybe a fauty Linux driver with a bug that does not show up with earlier virtualbox versions? Could any other user confirm that sound works well on VirtualBox 5.1.4 or 5.1.6 with both a Linux host and Linux guest?

Any help or info appreciated.

[mpack]

(4) I assigned two cores, and my system has 4 cores, not 2. But just in case, I tried with just one, and the trouble continues unchanged.

No, you have 2 cores. I already addressing this misunderstanding in advance, it's a pity you didn't absorb it. If you don't believe me then how about Intel? http://ark.intel.com/products/65707/Int ... o-2_60-GHz. You need to learn the difference between cores and threads.

You have an unsupported host, and in any case I suspect it's a guest problem (obviously: if VirtualBox prevented guests from playing video then everyone would have noticed it). Slackware is well known for its minimalist nature - no handholding - which obviously increases the likelihood of a configuration or dependency error. I suggest that you ask about this on a Slackware support site.