Add a pref to not skip frames

RESOLVED FIXED in Firefox 58

Status

()

enhancement
P2
normal
Rank:
15
RESOLVED FIXED
2 years ago
2 years ago

People

(Reporter: pehrsons, Assigned: pehrsons)

Tracking

58 Branch
mozilla58
Points:
---

Firefox Tracking Flags

(firefox58 fixed)

Details

Attachments

(2 attachments)

We'd need this for tests that record the screen (1080p, so quite slow) and then analyze the recording frame by frame.
Rank: 15
Priority: -- → P2
Assignee: nobody → apehrson
Status: NEW → ASSIGNED
florian, can you check whether this patch works for you?
Flags: needinfo?(florian)
Comment on attachment 8920115 [details]
Bug 1409727 - Add a mode and pref to disallow frame drops in MediaRecorder.

https://reviewboard.mozilla.org/r/191102/#review196516
Attachment #8920115 - Flags: review?(bvandyk) → review+
(In reply to Andreas Pehrson [:pehrsons] from comment #3)
> florian, can you check whether this patch works for you?

I had already answered on IRC last week, but repeating here to clear the needinfo:

With your patch applied and the pref flipped, I get a consistent 60fps when the mediarecorder input is an existing video file captured at 60fps, played in a <video> and then captured through video.mozCaptureStream(), so I would say the patch works for me.

However I didn't see a significant difference when the input stream was coming directly from my HDMI recorder using getUserMedia.
So either there's another bug for that case, or I have a USB bandwidth issue on the macbook.
Flags: needinfo?(florian)
What if you're doing a screenshare? It probably doesn't have the same high framerate, but it does have large frames.

Can you see differences if you record with ffmpeg straight off the device instead? https://trac.ffmpeg.org/wiki/Capture/Webcam#Encodingexample1

I think it's possible for us to drop frames before the recorder when the source is getUserMedia too (that video.mozCaptureStream() wouldn't be exposed to). But it would be good to confim whether that is what is actually happening here.

Related: I was preparing a script for QA last week, I was going to tell you on IRC but you had just left. It can help you analyse frames in a recording: https://github.com/Pehrsons/plotbitrate
Flags: needinfo?(florian)
The reason for missing frames with getUserMedia on Mac is bug 1412326.
Flags: needinfo?(florian)
Comment on attachment 8920114 [details]
Bug 1409727 - Expose the audio node recording pref to about:config.

https://reviewboard.mozilla.org/r/191100/#review200802
Attachment #8920114 - Flags: review?(jib) → review+
Pushed by pehrsons@gmail.com:
https://hg.mozilla.org/integration/autoland/rev/ea9eada6667e
Expose the audio node recording pref to about:config. r=jib
https://hg.mozilla.org/integration/autoland/rev/baf693d2380d
Add a mode and pref to disallow frame drops in MediaRecorder. r=SingingTree
https://hg.mozilla.org/mozilla-central/rev/ea9eada6667e
https://hg.mozilla.org/mozilla-central/rev/baf693d2380d
Status: ASSIGNED → RESOLVED
Closed: 2 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla58
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