Issue 1714 in webm: vp8 encoder integer overflows with high bitrate

[apehr… via monorail]

Status: Untriaged
Owner: ----
Labels: Type-Bug Pri-2
Components: libvpx

New issue 1714 by apehr...@mozilla.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714

I'm a Firefox developer. We use libvpx for encoding in MediaRecorder.

Steps to reproduce:
Prereqs: I had a local build with some WIP patches, and due to issue #1685 it also had libvpx updated to v1.9.0. I'm not sure how this repros on Firefox release channels. The fiddle will ask for 1920x1080, having a screen with a lower resolution or another aspect ratio might affect reproducibility.
1. Open https://jsfiddle.net/pehrsons/7kgvL48e/ in Firefox
2. Select Video, Screen and Max video bitrate. For max video bitrate enter "100000" for 100Mbps. (this is given to the vp8 encoder as target bitrate)
3. Click Start and approve prompts, selecting the full screen as source.
4. Wait ~30s. Keep fairly static content on screen.
5. Click Stop.
6. Put the video element in fullscreen, it's playing the finished recording.

Expected:
High quality video frames, given the high bitrate.

Actual:
Compression artifacts visible now and then, on key frames.

---

I have a pernosco recording of the above. The problem becomes obvious there. UBSan also highlights it. I'm attaching a screenshot showing the overflow in pernosco, and the output of a UBSan repro of the STR above.

Note in the screenshot that for all key frames but two, `cpi->this_frame_target` becomes negative.

Attachments:
Screenshot_2020-12-18 MediaRecorder inconsistent bitrate, w libvpx 1 9 0 (Pernosco).png 933 KB

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[sally… via monorail]

Comment #2 on issue 1714 by sally...@gmail.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c2

(No comment was entered for this change.)

Attachments:
Four_ The Transfer.html 2.4 KB

[jz… via monorail]

Updates:
Cc: ji...@google.com
Owner: mar...@google.com
Status: Assigned

Comment #3 on issue 1714 by jz...@google.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c3

(No comment was entered for this change.)

[ji… via monorail]

Comment #5 on issue 1714 by ji...@google.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c5

Hi,

there was a fix to an integer overflow problem in vp8:
https://chromium-review.googlesource.com/c/webm/libvpx/+/2998084

Could you please try this patch and see if this also fixes this issue?

Thanks.

[jz… via monorail]

Updates:
Labels: Needs-Feedback

Comment #6 on issue 1714 by jz...@google.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c6

(No comment was entered for this change.)

[jz… via monorail]

Updates:
Status: Fixed

Comment #7 on issue 1714 by jz...@google.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c7

Closing this due to lack of activity. If there is still an issue in Firefox please feel free to reopen this issue.

[apehr… via monorail]

Comment #8 on issue 1714 by apehr...@mozilla.com: vp8 encoder integer overflows with high bitrate
https://bugs.chromium.org/p/webm/issues/detail?id=1714#c8

Sorry for the late response. I can confirm this is fixed in recent libvpx.