571000 - Playing WebM videos on youtube is slow

Status: RESOLVED WORKSFORME

(Core :: Audio/Video, defect)

Description

[(no longer active)]

This seems to be the case because we're inefficient in resizing videos, which is what youtube does, at least for their 720p videos.

Comment 1

[bogas04]

It stutters here for first secs

Comment 2

[Jeff Muizelaar [:jrmuizel]]

(In reply to comment #1)
> It stutters here for first secs

That should be a separate bug.

Comment 3

[Nickolay_Ponomarev]

Attachment: sample

(I'd expect to find this bug in Video, not in Graphics.)

On my 2+ year old macbook with 10.5 the Activity Monitor reports 110+% CPU usage on a 360p video not in fullscreen (although the video still plays), the hot path is as follows. Is it what you call slow?

224 mozilla::layers::BasicImageLayer::Paint(gfxContext*, void (*)(mozilla::layers::ThebesLayer*, gfxContext*, nsIntRegion const&, void*), void*)
    224 _moz_cairo_fill_preserve
      224 _cairo_gstate_fill
        224 _cairo_surface_fill
          224 _cairo_quartz_surface_fill
            224 _cairo_quartz_draw_image
              224 CGContextDrawImage
                224 ripc_DrawImage
                  223 ripc_RenderImage
                    223 ripl_BltImage
                      215 ripd_Mark
                        215 argb32_image
                          215 argb32_image_mark
                            170 argb32_sample_argb32
                              170 argb32_sample_argb32
                            45 argb32_image_mark

Comment 4

[(no longer active)]

(In reply to comment #3)
> Is it what you call slow?

Isn't that what slow means?  :-)

Comment 5

[bugztemp]

Hi, I found this bug and saw it marked as Platform: x86 Mac OS X. It certainly is not a Mac problem only. YouTube webm is a currently a pain on Windows too.

This is on Vista x64 but as I'll mention later I also tested on another different system and got very similar results.

Processor is a 2GHz Core2 Duo. It was locked at maximum speed during testing (since power-saving downcloking could "water-down" the results.)

These are from a local (disk) 1280x720 @24fps webm file (downloaded from YouTube). It was always shown at 100% zoom factor (except obviously in fullscreen mode). 100% CPU means both cores loaded fully.

Video playing on hidden tab       15% CPU
Video visible                     55% CPU
Video visible, controls visible   65% CPU
Fullscreen                        20% CPU
Fullscreen, controls visible      70% CPU

So anything that is not video hidden or fullscreen without controls use disproportionate amounts of CPU. YouTube in-page is even worse because it'll resize the video and is obfuscated so you can't use the "good" fullscreen mode.

I also noticed that the modes which consume a lot of CPU seem to spend an inordinate amount of time in kernel mode (over 50%). This is usually a bad symptom (very slow system calls to blit the picture to the screen?). The hidden tab and fullscreen cases used basically zero kernel time.

I tested on another machine (a 3GHz P4), same story but worse results. I also tested 3.6.3 (with a Theora video), it shows similar performance (except fullscreen uses a lot of CPU even without controls).

I also tested a 720p video in YouTube using both Flash and HTML5 webm, playing resized at the "mid-large" size (about 853x480 pixels on screen). Here Flash used 35% CPU, and webm 80%. For videos that aren't resized, the difference isn't that big, but Flash is still faster.

Looking forward for a Firefox that performs a bit better out of fullscreen...

Comment 6

[Michał Gołębiowski-Owczarek [:mgol]]

My few coins:
Chrome dev with Webm: about 80% + 10% for two chrome processes, 8% Xorg
Firefox 64-bit dev with Webm: 125% firefox, 20% Xorg
Firefox 3.6.3 with Flash: 100% firefox, 7% Xorg

Everything on Linux x86_64 with 720p enabled, with larger frame (using the YouTube button - large video, not full screen).

CPU: Intel Core2 Duo P8600.

Comment 7

[Doug Sherk (:drs) (inactive)]

Please re-open if this is still an issue.