Youtube on G4 mini 1.25 GHz awfully stuttering or won't play

aargl's Avatar


15 Jun, 2020 09:52 PM

I'm giving a new try with mp4 enabler installed. On a clean profile, it's awfully stuttering, but in my main profile it won't even play and the web console says:
mutating the [[Prototype]] of an object will cause your code to run very slowly; instead create the object with the correct initial [[Prototype]] value using Object.create scheduler.js:22:60
mutating the [[Prototype]] of an object will cause your code to run very slowly; instead create the object with the correct initial [[Prototype]] value using Object.create 5k7CCto5.html:40:876
mutating the [[Prototype]] of an object will cause your code to run very slowly; instead create the object with the correct initial [[Prototype]] value using Object.create 5k7CCto5.html:40:876

MSE checkbox is worse. Changing user agent doesn't have any effect.
Addons off or starting in safe mode gives the same errors.

It's very likely that some settings in my main profile have been changed years ago (I recall trying some optimization tricks... ;-) ), have you got any idea which one could provoke those messages?
I know I should start over with a clean profile but this one is working nicely everywhere else and I think the possible settings changes are few, so if I can avoid...

And do you think it's possible to play Youtube smoothly on that machine, optimizing some setting? (Hardware wise, I've got an SSD in it and RAM is maxed out)

  1. Support Staff 1 Posted by Chris (chtrusch... on 19 Jun, 2020 08:56 AM

    Chris (chtrusch)'s Avatar

    'mutating the [[Prototype]]' has nothing to do with Youtube. Please load this video:
    What do you see in the area of the page in which the video should play? An error message? Just a black screen?

    For a clean profile: Please see the FAQ:

    Also: I noticed that Youtube tends to choose webm over mp4 with TenFourFox. If you want to ensure mp4 is used (which performs significantly better than webm on my PowerBook G4 1.67 GHz, for anecdotal evidence) you must disable webm: In about:config set media.webm.enabled to false.

  2. 2 Posted by aargl on 19 Jun, 2020 09:38 PM

    aargl's Avatar

    Thanks Chris!
    As for any Youtube video, I see a still image (i.e. the cat at the crossroads ;-) ) and a spinning circle.

    On a clean profile, I followed the FAQ's advices:
    1) it autoplays even if the autoplay switch is off — is an addon needed to fix that? I haven't found one that can install and works...
    2) about MSE, it's hard to tell which is better... in both cases (checked or unchecked) it has moments of "near-fluidity" and others when it stops for a while, mostly depending on image contents — and wether I leave the mouse pointer upon the video or not.
    3) setting media.webm.enabled to false gave mixed results, but in the end it's the overall best option — with MSE checked, though I thought it was only acting on vp8/vp9 — and I have to park the pointer outside of the video area.

    In the end, what we'd need is something to prevent Youtube from loading the whole page full of useless stuff and prevent autoplay before the buffer completely loads...

  3. Support Staff 3 Posted by Chris (chtrusch... on 19 Jun, 2020 11:28 PM

    Chris (chtrusch)'s Avatar

    I have no idea what prevents the video from loading correctly. Try re-starting the browser with add-ons disabled (Help>Troubleshooting Information…) to see if an add-on is blocking the content.

    The autoplay toggle on Youtube simply means the next video is automatically selected and played. There used to be add-ons that prevented autoplay (in the sense a sane person would interpret the meaning of the word), but they never worked reliably, and then stopped working altogether.

    tenfourfox.mp4.high_quality should be set to false for maximum performance.

    Here's what I do: As soon as the video starts playing, click Pause, then immediately select 144p, 240p or 360p (whichever your Mac can handle at the most). Wait until the page and the video buffer have stopped loading and the CPU load of the browser has gone down. Then click Play.

  4. 4 Posted by aargl on 20 Jun, 2020 10:48 AM

    aargl's Avatar

    Addons off is the same, but I've started resetting that profile anyway, as it's quite light (despite the many trials I've done across the years, it has only uBlock Origin active).
    It's my 87 year old mother's computer, so I try to make it as simple and clean as possible. ;-)

    I came to the same conclusion/procedure as you, except that mine seems to never select a resolution above 240p (with MSE checked), so even better. :-)
    Additionally, I've filtered out the right column and the comments using uBlock ( and

    An interesting option I've found is to set media.mediasource.enabled to false for the video to buffer completely! But apparently it won't allow resolutions under 360p, so for me it's Stutteringland again. ;-) Maybe this will suit your PowerBook.

  5. 5 Posted by aargl on 22 Jun, 2020 10:24 AM

    aargl's Avatar

    Thanks again, Chris, for your help!

    In conclusion to all my trials (for anyone coming here in search of a guide ;-) ):

    • resetting the profile didn't really change anything but it's always good to start over on a clean basis

    • filtering out the right column and the comments using uBlock is improving the page load time a lot (and also the fluidity!)

    • applying all possible FF tweaks (pipelining and foxPEP — gives a very slight improvement — I must say I've never seen a huge benefit in those tweaks, they're not "blatantly faster" as some say in those forums... Be careful: some of those tweaks are even counterproductive in slow machines! (such as nglayout.initialpaint.delay=0)

    • setting nglayout.initialpaint.delay to 2000 or even 4000 doesn't change anything, as I've never seen any site loading in less than 4s on that machine... But it doesn't hurt. ;-)

    • setting media.webm.enabled to false, with MSE checked is definitely the best compromise. Here it seems to select the suitable resolution by itself (144p or 240p), or maybe Youtube remembers the last one I chose.

    => Then, parking the mouse pointer outside of the video area and not moving the mouse while playing is mandatory.

    => Pausing the video and waiting for the buffer to fill up allows for a better fluidity right from the start, but if you don't mind a bit of stuttering, it will load anyway and attain fluidity after a while.

    EDIT: I've then tried boxing Youtube ( and while it's better than Youtube as it normally is, it's not better than the browser version + uBlock filtering and the settings mentioned above.

  6. 6 Posted by aargl on 22 Jun, 2020 12:48 PM

    aargl's Avatar

    Breaking news: I've just discovered, reading some forum, that is serving the same videos as Youtube but in a bare-bones way! Consequently, it's faster to load, no useless stuff and might allow for better resolution. :-o
    There are downsides, though: on my Mini G4 it selects 480p or even higher resolutions which that poor old chum can't bear. Such a pity there's not a global setting for a preferred resolution.

    EDIT: Boxing gives a whole lot better result than with Youtube, making even 360p playable on that machine. Unfortunately, most of the results of the queries are always in English, no matter if the prefs of the site are set to French...

  7. 7 Posted by Ken Cunningham on 06 Jul, 2020 10:15 PM

    Ken Cunningham's Avatar

    You can get the (usually) latest version of smtube via macports (sudo port install smtube). It works just great on 10.4 PPC all the way up to -- last I tried was High Sierra I think.

  8. 8 Posted by Ken Cunningham on 06 Jul, 2020 10:18 PM

    Ken Cunningham's Avatar

    oh -- there is a global setting for the resolution. it's the first item in "preferences".

  9. 9 Posted by aargl on 07 Jul, 2020 08:55 AM

    aargl's Avatar

    Thanks for the suggestion. From the screen captures I found, it looks like smtube behaves like tonvid, so I suppose my issue with the results being in English will be the same (the computer is used by a strictly French speaking person).

  10. 10 Posted by Ken Cunningham on 07 Jul, 2020 09:48 AM

    Ken Cunningham's Avatar

    Could be. It's writtten in qt4, and there are translation file for about 15 languages in it, but I never use them and mihjt have put them in the nwrong place to make them work.

    I could use some help with that. There's a new update in the PR queue now <>.

    MPorts is pretty essential if you have Tiger I think -- I have about 1000 ports installed at present on ,mine.

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