Muito Bom Puntuado con 5 de 5 estrellas

Não tava dando pra ver lives, agora, graças a esse add-on, eu posso ver as lives dos meus Youtubers favoritos =3. Obrigado aos desenvolvedores <3. Vocês são demais!.

Funciona perfectamente Puntuado con 5 de 5 estrellas

Forza a trabajar con Flash engañando a Youtube. Magnífico...

Doesn't always work Puntuado con 1 de 5 estrellas

I have all the pre requisites and confirmed my config settings are enabled. I still get the youtube message that browser does not recognize any formats available.

Youtube Videos STILL not loading Puntuado con 3 de 5 estrellas

It was just updated today. YT decided to disable Flash permanently and it wasn't loading the videos at all. So installed this as well as several others today to get YT working again. Alas, it is not. Tried with versions 43 through 53. Am I really being forced to use 55 beta by Mozilla (AKA the Other Chrome)? Hopefully, Klemens will succeed in resolving this nightmare for all of us. :)

Puntuado con 5 de 5 estrellas

Intento ver vídeos de you tuve en firefox

Doesn't fail Puntuado con 5 de 5 estrellas

It doesn't fail at changing quality and auto pausing like some other add-ons.
Unfortunately Context menu item to open video without playlist is appearing on some other sites instead only on Youtube.
It would be also great if you could add an option to prevent videos load in theater mode when I close previous tab with it. I mean force to open always in default mode (small player on left). The option that already is there centers it on the page, which I don't want to.

Great, but new YT update broke it Puntuado con 5 de 5 estrellas

Works great, but it was broken by the new YouTube layout (which can be enabled at

Este usuario tiene una valoración anterior de este complemento.

Yup, I will try to find the problem as soon as I have some time. This was also reported on GitHub [1], where you can follow the progress if you want.


Icon on toolbar Puntuado con 5 de 5 estrellas

Please add icon to this addon on toolbar, as a short cut to options. It will be helpful... Beside this- great addon!

Does not work for me but am I really the only one? Puntuado con 1 de 5 estrellas

Anyway, will try to keep it short; but basically this causes YouTube to load a black screen. I can see the video buffering, but nothing is playing.

I click on it and then it switches to PAUSE icon. I click on it again and then it does the spinning loading graphic. If I manually jump ahead in the video it plays normally.

I do not have FLASH installed. I finally removed this and just installed - DISABLE HTML5 AUTOPLAY - and everything works normally. No flash so Firefox should be loading HTML5 by default, but the autoplay seems to load a black screen. With this OTHER Add-On it is paused and the click loads and plays the HTML5 video fine.

5 stars - i love it! Puntuado con 5 de 5 estrellas

so many functions this small fucking cool and helpfull addon bravo!
for me 5 stars!

Esta valoración es de una versión anterior del complemento (3.1.0). 

Nice but... Puntuado con 5 de 5 estrellas

Very nice. But I wish it also works in YouTube videos embedded in other websites.

Esta valoración es de una versión anterior del complemento (3.1.0). 

Thank you!

What feature would you like to work in embedded videos? The add-on already tries to also force html5 in embedded videos.

almost perfect just a suggestion Puntuado con 4 de 5 estrellas

You're missing an option to use mp4 (h264) as the preferred format
while google prefers mp4 on windows vista+ it forces webm on Linux's

there are several reasons to prefer h264 instead of vp9 as:
#1 hardware decoding only recent and expencive gpu's have vp9 hardware decoding while 10 year old gpu's can decode h264
#2 Video quality
this is subjective but imo there is a lot less pixelation and ringing in h264 compared to vp9
#3 File size
mp4's are 5-10% smaller then the equivalent webm files

afaik hardware decoding is done by the backend ie ffmpeg
(gstreamer was dropped by mozilla) I might be wrong but I do belive ffmpeg does hardware decoding if your hardware supports it
only new nvidia chips have partial vp9 support 960 and above (titan X has full)
and on intel's side partial vp9 support was introduced with the Skylake processors (full with Kaby Lake)
only a fraction of desktop hardware has vp9 support
regarding vp9 30% smaller lol that's google propaganda for example at 360p
the mp4 is 40.7M
the webm is 53.2M and is 7% bigger
I am using this script to get the file sizes
it doesn't get webm's at higher res I'm not sure why

still I think it's google's bug if it sees Linux in the browser user agent it prefers vp9 I ended up disabling webm
but I think you can add an option to prefer h264

Esta valoración es de una versión anterior del complemento (3.1.0). 

While I agree that some older systems might have problems decoding high-res VP9 videos, the same is true for H264, as firefox currently does not support any video hardware decoding on linux [1]. And when comparing decoding speed, VP9 is typically equally fast when comparing videos with the same quality, because in VP9 they then need a much lower bitrate [2, section "Decoding speed"].

This is also the reason why VP9 videos on youtube are in every case I have seen smaller than their H264 counterparts, usually around 30 to 40 % (you can easily check all available resolutions and their sizes using youtube-dl).

But like mentioned in the description, if you really want, you can control WebM/VP9 with the media.mediasource.webm.enabled setting in about:config. Note that the youtube html5 test site has a bug in that it shows VP9 as enabled even if it is not, however it falls back to H264 when actually playing a video.


I did a test and VP9 and H264 decoding resulted in exactly the same CPU usage on my system. about:support also tells me under "Hardware H264 Decoding" that it is not supported, even though it uses ffmpeg as backend on my system as well.

Regarding the sizes of the video you mentioned, this is what youtube-dl tells me: (excerpt)
243, webm, 640x360, DASH video 457k, vp9, 24fps, video only, 21.59MiB
134, mp4, 640x360, DASH video 606k, avc1.4d401e, 24fps, video only, 24.65MiB
244, webm, 854x480, DASH video 823k, vp9, 24fps, video only, 37.29MiB
135, mp4, 854x480, DASH video 1112k, avc1.4d401e, 24fps, video only, 46.88MiB
247, webm, 1280x720, DASH video 1635k, vp9, 24fps, video only, 73.36MiB
136, mp4, 1280x720, DASH video 2206k, avc1.4d401f, 24fps, video only, 81.69MiB
So VP9 is smaller in every case there as well.

The difference you see are these non-mse files:
43, webm, 640x360, medium, vp8.0, vorbis@128k, 53.23MiB
18, mp4, 640x360, medium, avc1.42001E, mp4a.40.2@ 96k, 40.73MiB
But the webm file in this case contains VP8 and not VP9 and a higher bitrate audio track, so naturally it is larger.

Regarding a setting to disable VP, what is wrong with media.mediasource.webm.enabled?

Some new problems with other add-ons in latest version Puntuado con 3 de 5 estrellas

(Response to my previous rating and the dev comment)


It seems that with the latest version there are some problems with /some/ videos which do not start uninitialized in conjunction with the FlashStopper add-on;
You mentioned that you redid the "Start videos paused" option (which indeed seems to work more reliable now when enabled) but since it still displays an ugly black screen (and also initializes the video in the first place) I chose to set it to "Never" and let the "FlashStopper" add-on do this instead.

Unfortunately I think the redone option messes with FlashStopper as they might be accessing the same variable and override each other or something so that some videos start uninitialized (the way I want it) while others start playing right away (which is somewheat annoying).

Would it be possible for you to add an option to start the video uninitialized (with the thumbnail and play-button in the middle) instead, even if there hasn't been much demand for this yet, as you said before?


The same goes for when the video has finished: In that regard the "Prevent autoplay of recommended videos" option is nice but it should not remove the thumbnail in the background and the recommended video tiles that appear when pressing cancel on the autoplay without this add-on.


I'm not sure that the "Video playback rate" option is needed since the HTML5 player on YouTube already has that option built-in but it's only used once every blue moon.


I like the new "Video volume" option however, since I like to keep the volume at 50% so I have room to go up or down. So it's nice to have the 50% value in there. Although I think other people might find the rest of the values a bit sporadic. I don't think I remember any add-on with a slider (for precise percent values) on the options page within the about:addons page (maybe not even add-ons which open their own small options window) so I'm not sure whether this would be even possible. Alternatively I'd suggest to make the values go up in 10% increments instead. Or a numeric input field which get's clamped between 0 and 100% if that's possible.


Keep up the good work! ;)

Esta valoración es de una versión anterior del complemento (3.1.0).  Este usuario tiene una valoración anterior de este complemento.

Thanks for your response! (you can also send me an email or open an issue at github if you like)

I am not sure how the new "start paused" option could interfere with FlashStopper, as it literally does nothing [1] when the feature is not enabled. Does this always happen with the same videos? If yes, could you send me an example? I will have a look at a hypothetical "Start videos stopped" option for the next release.

The "Prevent autoplay" option does exactly the same as the slider that is present on every youtube video page by default (by sending the same cookie that youtube uses to store this setting), so if this results in the recommended video tiles in the player being hidden, this is likely a bug of youtube or another extension.

The playback rate, volume, hide annotations and prevent autoplay features (which are all available directly through the youtube interface) are mainly targeted at users who regularly delete their cookies and so loose their settings.

I tried to make a compromise with the volume levels, because a slider or a numeric field with +/- buttons is unfortunately not possible. I don't like simply putting a textbox there, however this may be nonetheless the most practical solution, we'll see.


Convert to non-sdk Puntuado con 5 de 5 estrellas

Hi. I use the Pale Moon browser and version 27 will make jetpack/sdk extensions not work. I love this extension and would love to continue to use it. Can you please convert? Thanks!

Esta valoración es de una versión anterior del complemento (3.0.3). 

That is really unfortunate, as the addon makes heavy use of some add-on sdk features.

What do you mean with non-sdk? A classic restartless XUL extension or a WebExtension? As firefox is working on dropping XUL support, I won't convert the addon to the former, sorry.
However as the APIs for WebExtensions become more complete, I think I'll try porting the addon to it. I am not sure what Pale Moon plans to support in the long term, but it currently seems they won't support WebExtensions any time soon.

Having said that, it is certainly *possible* to convert the addon to a classic XUL addon, I just won't be the one doing it. But if anyone wants to try that, I will happily answer questions.

Edit: The new version 3.1.1 now supports pale moon starting with pale moon version 27.1!

Nope Puntuado con 1 de 5 estrellas

Doesn't work. Turned all my videos black instead. I can't find anything that actually works.

Esta valoración es de una versión anterior del complemento (3.0.3). 

I am sorry that it does not work for you. You can open an issue at github ("Support site") or send me an email if you want and I will try to help you debug this problem.

Some information that would be useful are the version of the addon, os and firefox you are using and if you have flash installed and/or enabled.

You could also try the new beta version 3.1.0 beta 3 ( and see if it works with that.

Thanks Puntuado con 5 de 5 estrellas

perfect to pc low very very low

Esta valoración es de una versión anterior del complemento (3.0.3). 

Puntuado con 3 de 5 estrellas

I had some problems with this. It worked sometimes ... and sometimes didn't. Good idea, though.

Esta valoración es de una versión anterior del complemento (3.0.3). 

Could you be more specific about the things that don't work as expected?
I also just uploaded a new beta version that fixes some long-standing problems, see here for details:

Great! Puntuado con 5 de 5 estrellas

It's working.

Esta valoración es de una versión anterior del complemento (3.0.3). 

Wonderful! Buh-Bye slow and crashy FlashPlayer. Puntuado con 5 de 5 estrellas

Since Macromedia convinced coders that Flash was the future, I have hated it. It's slow, crashy, and just plain annoying. This add-on is fixing my internet experience. I only wish it worked on everything flash!

Esta valoración es de una versión anterior del complemento (3.0.3). 

Not tech-savvy Puntuado con 1 de 5 estrellas

Don't know enough to configure and maintain an alternate OS, and will not spend more money on Microsoft product.

The lack of support for XP is understandable in context but disappointing.

It's good to be one day closer to death.

Esta valoración es de una versión anterior del complemento (3.0.3). 

I can understand your anger, but this is a firefox problem. Firefox does not support H264 under windows xp, because the H264 codec is only built into windows since vista.

Although this might seem as a strange advice, you could try chrome which seems to support h264 under xp as yet.

Edit: It seems Firefox supports VP9/MSE under Windows XP, which should make YouTube work without problems.