[tor-commits] [tor-browser/tor-browser-52.5.2esr-8.0-1] Bug 22548: Firefox downgrades VP9 videos to VP8.

[gk at torproject.org]

commit 9080c51a22a03aaf8e49d5552253ed716414c760
Author: Fernando Fernandez Mancera <ffernandezmancera at gmail.com>
Date:   Sat Jan 6 21:26:05 2018 +0100

    Bug 22548: Firefox downgrades VP9 videos to VP8.
    
    On systems where H.264 is not available or no HWA, VP9 is preferred. But in Tor
    Browser 7.0 all youtube videos are degraded to VP8.
    
    This behaviour can be turned off by setting media.benchmark.vp9.threshold to 0.
    All clients will get better experience and lower traffic, beause TBB doesn't
    use "Use hardware acceleration when available".
---
 browser/app/profile/000-tor-browser.js | 2 ++
 dom/media/Benchmark.cpp                | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/browser/app/profile/000-tor-browser.js b/browser/app/profile/000-tor-browser.js
index 32922418b12f..1302d2e2d6be 100644
--- a/browser/app/profile/000-tor-browser.js
+++ b/browser/app/profile/000-tor-browser.js
@@ -160,6 +160,8 @@ pref("javascript.use_us_english_locale", true);
 // pref("intl.charsetmenu.browser.cache", "UTF-8"); // Set by Torbutton
 // Disable video statistics fingerprinting vector (bug 15757)
 pref("media.video_stats.enabled", false);
+// Set video VP9 to 0 for everyone (bug 22548)
+pref("media.benchmark.vp9.threshold", 0);
 // Disable device sensors as possible fingerprinting vector (bug 15758)
 pref("device.sensors.enabled", false);
 pref("dom.enable_resource_timing", false); // Bug 13024: To hell with this API
diff --git a/dom/media/Benchmark.cpp b/dom/media/Benchmark.cpp
index a4761f1b1ec8..2364ac2fa79c 100644
--- a/dom/media/Benchmark.cpp
+++ b/dom/media/Benchmark.cpp
@@ -79,7 +79,7 @@ VP9Benchmark::IsVP9DecodeFast()
 
   uint32_t decodeFps = Preferences::GetUint(sBenchmarkFpsPref);
   uint32_t threshold =
-    Preferences::GetUint("media.benchmark.vp9.threshold", 150);
+    Preferences::GetUint("media.benchmark.vp9.threshold", 0);
 
   return decodeFps >= threshold;
 #endif