Open Bug 1588042 Opened 5 years ago Updated 16 days ago

Unable to control video buffering using media.cache_readahead_limit media.cache_resume_threshold

Categories

(Core :: Audio/Video: Playback, defect, P5)

69 Branch
defect

Tracking

()

UNCONFIRMED

People

(Reporter: underpass_bugzilla, Unassigned)

Details

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

Hello,

One user of the Italian forum has pointed out that in the last version of Firefox it isn't possible to control the size of the buffer stream using the solution given here:

https://support.mozilla.org/en-US/questions/1168957

Actual results:

I've set both values to 99999 and tried with a YouTube video. The size of buffered data don't seem to change since the download speed rate more or less remains the same.
This also happen in Beta and Nightly.

Expected results:

I would expect Firefox to download a bigger amount of data with both preferences set at 99999.

Thanks.

Hi Underpass!

To try to reproduce this bug, we need a little more information. Is it possible for you to send us the link of the video you had problems with?
Also, could you send us a screen record where you can see that the buffer size does not change?

Thanks for your cooperation!.

Flags: needinfo?(underpass_bugzilla)

Hello,

I experienced the problem with a "normal" YouTube video such as

https://www.youtube.com/watch?v=Js0c52IiaBA

I would expect, changing those parameters, that the video got buffered more quickly. But this doesn't happen.
I left a note to the user who was complaining the problem asking him to provide the information you require.
But you can also test it by yourself: with a new Firefox profile, try to play that video and take note of the buffer rate. Then change the two settings and see if the video gets cached more quickly.

Flags: needinfo?(underpass_bugzilla)

I was unable to reporduce it.
I'll add a product and component so the corresponding team can take a look at this.

Component: Untriaged → Audio/Video: Playback
Product: Firefox → Core
Priority: -- → P5

Hello, I'm actually the one who has the problem, thanks for the time spent on it. Just created an account to give more details.
The question was already asked in official Mozilla forum, but with little results (you can also find details there):
https://support.mozilla.org/en-US/questions/1270107

I really can't say 100% that this is a bug, my original question was about setting parameters configuration in about:config right. I mean, after the first change in 2017, video were not totally buffering anymore, so I've read in that thread a solution that has worked:
https://support.mozilla.org/tr/questions/1168957

Since a few weeks, doesn't work anymore, so maybe something has changed in a recent version, and some of my parameters could create a conflict, or something like that. Maybe the first solution isn't the right one the way the browser has changed.
So, the secondary point was to find an user that is able to buffer all the video, confronting the parameters and see what he has to make it work.

Answering your previous questions:

  • that issue happens in every video, youtube, dailymotion, eurosport player, and any other video that is charged in news sites.
  • I could make a screen shoot, but being an image, you would see the buffer size that obviously doesn't change. Don't know how to make a shoot record, but I can assure you 100% that is not buffering anymore after a short time. It happens in every video since quite a few weeks.

Any update on this? More details are needed?

I can add one more "unwanted" test.
The motherboard of my laptop died a week ago, so I had to come back to my old laptop, that has still window7 installed and is a older model.
I've installed Firefox there, and then copied all the parameters of my profile to have all my settings back.
And after that, the problem is still the same, the buffering stops after a short time, confirming my idea that is a parameters issue.

Any help would be appreciated. Thanks again.

I have the same problem, i wanted to buff 2hrs video but it only buff and stuck on 32mins.
I tried other video engine but still the same probem. Im using firefox 71
media.cache_readahead_limit 99999
media.cache_resume_threshold 99999

I set these options to 9999, but FF seems just ignoring them. Can't watch video at weak internet connection.
However my case is DRM-protected video, does it have different controls?
FF 75, Fedora 32 x64

DASH enabled services and players have never been controlled by these prefs.

Thanks, it appears to be my case - I disabled media.mediasource.enabled and video page just refused to play movie with "No compatible source" error message.
media.cache* preference names seem misleading a bit.

So, no way to increase buffers for DASH media?
Did a bugzilla search and don't see anything related.
Is it worth to create a separate bug?

Alternatively it should help in this case to force minimal resolution (that player can't do this) - but that's another question.

Severity: normal → S3

I can confirm that current Firefox ESR 115.8.0 is still affected by this bug. It is as Danial Horton mentions in comment 8. Many video websites now use Dynamic Adaptive Streaming over HTTP (DASH) and the user is unable to adjust the video buffer size with the following "about:config" settings:

media.cache_readahead_limit
media.cache_readahead_limit.cellular
media.cache_resume_threshold
media.cache_resume_threshold.cellular

Those settings seem to still work if the video website does not use DASH, but such websites are increasingly rare.

For me DASH on most websites works fine since I usually have relatively fast and reliable connection (usually at least 100/100 Mbit). Problems with the small video buffers however do occur for me when a video website server has a slow reaction to my Firefox demanding new data.

Then I see the video buffer quickly exhausted and the video is paused waiting for some slow server with a limited bandwidth to be so kind to send the next idiotically small chunk of data, so that I can experience the video pausing again in ~ 60 seconds. This mostly happens with less popular or older videos on websites that probably offload such videos to servers with limited bandwidth or something. But the fact that Firefox does not let the user adjust the video buffer size for DASH is still really annoying and usually forces me to give up and stop watching the problematic video. Because disabling DASH with "media.mediasource.enabled" either limits the video quality the website provides or disables the video playback completely in many cases (as mentioned in comment 9).

For such cases it would help if the user could adjust the DASH buffer size (Is there some "about:config" setting I overlooked?) or if Firefox automatically increased the buffer size after it detects that the video buffer underflow occurs more often (e.g. 2 or 3 times in a row or some interval). Firefox could even ask the user if the whole video should be buffered in those cases and buffer the video only if the user wants it to prevent wasting network bandwidth.

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