Jerky video playback

[Bret Busby]

On 15/6/23 02:31, Ralf Mardorf via ubuntu-users wrote:
> On Thu, 2023-06-15 at 00:32 +0800, Bret Busby wrote:
>> And, in the context of my last paragraph above, similarly, do you get
>> similar problems when viewing the problematic videos, with mpv?
> 
> When I tested hardware video acceleration a long time ago, I added a
> command line option to IIRC mpv.
> 
> DE
> 
> "SMPlayer: Optionen -> Einstellungen -> Leistungsverhalten ->
> Entschlüsselung --> Geräteentschlüsselung "Automatisch"" -
> https://wiki.archlinux.de/title/Hardwarebeschleunigung#Hardwarebeschleunigung_aktivieren
> 
> EN (translated by Google ;)
> 
> "SMPlayer: Options -> Settings -> Performance -> Decryption --> Device
> decryption "Automatic"" - https://www.google.com/search?q=translate
> 
> 

That modification causes me to think of another possibility.

I have been using mpv, off and on (mostly by accident), without any 
problems, that I remember, as I have also been using SMPlayer 
(primarily), and, on occasion, vlc (which has the advantage over 
SMPlayer, in that vlc can record extracts from videos being viewed, and, 
sometimes, Celluloid (probably as my secondary video viewer - amongst 
other things, I use it to quickly determine the (time) length of videos, 
which I insert into the file names of some videos), and, as said, on 
occasion, mpv.

The only problems with jerkiness and lack of fluidity and continuity, 
that I have encountered while viewing videos, have been, from my 
understanding, from two causes.

The first perceived problem cause, is when I have insufficient available 
resources - when the memory usage and the system load average, are too 
high (hence, my reference to these items, in a previous message in the 
thread), and, the second perceived cause (although, this mainly applies 
to viewing videos with the web browser (firefox) ), I believe to be due 
to watching streamed videos, with lack of continuity in the streaming.

Now, the possibility that occurred to me, after reading of the 
modification that Ralf made (Ralf said that he though it was to mpv, 
but, the detail indicated that it involved SMPlayer (which I believe, is 
a front end to mplayer, rather than to mpv) - I am not criticising, just 
making the observation), as Ralf's reference includes
"I tested hardware video acceleration a long time ago", is the reference 
to hardware acceleration.

My understanding is that a computer has a GPU, and, in addition to a 
GPU, the computer can also have a graphics accelerator, which leads me 
to thence wonder, as I am using nVIDIA graphics, with Optimus on some of 
my computers, whether the original poster's problems have something to 
do with the graphics hardware in the system, and, whether the 
appropriate graphics drivers are installed, and, whether any 
incompatibility problems between the videos and the graphics hardware 
(also, considering whatever are the applicable screen resolution and 
refresh rate, and, whether they are compatible with both the particular 
videos, and, with the video viewing software.

I think that the GPU, and, if applicable, the graphics accelerator, and, 
the applicable drivers (for example, if nVIDIA Optimus is in the system, 
whether the Ubuntu driver (nouveau (?) ) or the applicable (and, 
especially, appropriate) nVIDIA driver, is installed and being applied), 
have not been specified, by the original poster, in case the problem 
lies somewhere with an incompatibility between them and the video 
player, and/or, the particular, problematic videos.

Ralf, and others, are far more knowledgeable, than me, about all of 
this, but, these are just some thoughts about this, that occurred to me.

..
Bret Busby
Armadale
West Australia
(UTC+0800)
..............