1305296 - MSE & WebM VP9 is unexpectedly enabled in youtube even if media.mediasource.webm.enabled = false by default

Status: RESOLVED WONTFIX

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

Description

[Alice0775 White]

[Tracking Requested - why for this release]: Regression, unable to disable "MSE & WebM VP9" with preferences

Steps To Reproduce:
1. Make sure default media.mediasource.webm.enabled = false in about:config
2. Open https://www.youtube.com/html5
3. Observe "MSE & WebM VP9"

Actual Results:
"MSE & WebM VP9" is enabled

Expected Results:
"MSE & WebM VP9" should not be enabled because media.mediasource.webm.enabled = false 


Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=302dab53de80ffaa66152776fa874a5b6868d629&tochange=b66c40900f63648204ce9b34780982be224aeda0

Regressed by:1eb286442c40	Gerald Squelart — Bug 1267970 - Block hw decoding on ati up to 16.300.2311.0 - r=kentuckyfriedtakahe



Graphic section of both good/bad build are as follows.


*** Before landing Bug 1267970 ***
Graphics
--------

Features
Compositing: Direct3D 11
Asynchronous Pan/Zoom: none
WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon HD 6450 Direct3D11 vs_5_0 ps_5_0)
WebGL2 Renderer: ATI Technologies Inc. -- AMD Radeon HD 6450
Hardware H264 Decoding: No; D3D11 blacklisted with DLL atidxx32.dll (8.17.10.648); D3D9 blacklisted with DLL atiumd64.dll (9.14.10.1171)
Audio Backend: wasapi
Direct2D: true
DirectWrite: true (10.0.14393.0)
GPU #1
Active: Yes
Description: AMD Radeon HD 6450
Vendor ID: 0x1002
Device ID: 0x6779
Driver Version: 15.301.1901.0
Driver Date: 2-26-2016
Drivers: aticfx64 aticfx64 aticfx64 amdxc64 aticfx32 aticfx32 aticfx32 amdxc32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Subsys ID: 23111787
RAM: 1024

Diagnostics
ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 300
AzureCanvasAccelerated: 0
AzureCanvasBackend: direct2d 1.1
AzureContentBackend: direct2d 1.1
AzureFallbackCanvasBackend: cairo
ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 300



*** After landing Bug 1267970 ***
Graphics
--------

Features
Compositing: Direct3D 11
Asynchronous Pan/Zoom: none
WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon HD 6450 Direct3D11 vs_5_0 ps_5_0)
WebGL2 Renderer: ATI Technologies Inc. -- AMD Radeon HD 6450
Hardware H264 Decoding: No; Hardware video decoding disabled or blacklisted
Audio Backend: wasapi
Direct2D: true
DirectWrite: true (10.0.14393.0)
GPU #1
Active: Yes
Description: AMD Radeon HD 6450
Vendor ID: 0x1002
Device ID: 0x6779
Driver Version: 15.301.1901.0
Driver Date: 2-26-2016
Drivers: aticfx64 aticfx64 aticfx64 amdxc64 aticfx32 aticfx32 aticfx32 amdxc32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Subsys ID: 23111787
RAM: 1024

Diagnostics
ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 300
AzureCanvasAccelerated: 0
AzureCanvasBackend: direct2d 1.1
AzureContentBackend: direct2d 1.1
AzureFallbackCanvasBackend: cairo
ClearType Parameters: Gamma: 2.2 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 300

Comment 1

[Jean-Yves Avenard [:jya]]

This is as intended.

MSE is enabled by default for the VP9 codec if any of the following conditions are met:
1- Machine is deemed fast enough to decode VP9 (current threshold is the ability to decode a 720p stream faster than 150fps)
2- H264 decoding isn't supported (like on Windows XP)
3- HW H264 decoding isn't available

Comment 2

[Jean-Yves Avenard [:jya]]

should add:
4- media.mediasource.webm.enabled is set to true

Comment 3

[Marcia Knous [:marcia]]

Not tracking this for 52.