"shaka-player with MPEG-DASH" gives me error

[Moonchild]

In fact, it is a slightly strange reason for ignoring preferences: "The CPU is considered to be fast enough"...

This seems to be a result of https://bugzilla.mozilla.org/show_bug.cgi?id=1213177 where VP9/MSE is enabled for systems that don't have WMF or have no hardware decoding capabilities at all for h.264. So if your configuration simply cannot play MP4 videos anyway then it will enable VP9 on-the-fly. Ignoring a pref and being able to play video was considered better than not being able to play at all, it seems.

[Kris_88]

Ignoring a pref and being able to play video was considered better than not being able to play at all, it seems.

Yes, it is logical. But they use "OR", so this returns TRUE when IsVP9DecodeFast()==TRUE regardless of the remaining conditions.
return !mp4supported || !hwsupported || VP9Benchmark::IsVP9DecodeFast();

However, this does not cancel the fact that Shaka-player must check the video stream and somehow process the error.

[Moonchild]

Won't be the first time that Mozilla's decision making isn't particularly logical.

[coffeebreak]

The player may not work, because in some cases "MSE for WebM Video" may be turned on implicitly forcibly.
See IsWebMForced() ...
As a result, the player believes that the .webm has a video stream and tries to play it. But in fact there is no video stream, there is only audio.

Kris_88, thank you so much for posting all of this. Very informative.

Mozilla's decision making

Seems panic-driven (because some users no longer had access to higher resolutions on YouTube).
(bug #1217170 - the bug you posted mentions in a comment these two are likely duplicates)

[Kris_88]

I figured out why an error occurs in the Shaka player.
The reason was deeper than it seemed to me first.
In the .mpd file the name of the codec is indicated in the new notation:
codecs="vp09.00.11.08.00.02.02.02.00"
The player checks whether the browser supports a new notation and even installs polyfil, which converts new notation to the old one ( "vp09. XX.XX..." -> "vp9" ). However, polyfil works only for the isTypeSupported() function but not for the addSourceBuffer() function.
Without a doubt, it is flawed in the player. However, since the new notation appeared and already used, then over time problems will arise with other players. It is desirable that the PM will support a new format.
https://developer.mozilla.org/en-US/doc ... meter#webm
ISO Base Media File Format syntax: cccc.PP.LL.DD.CC[.cp[.tc[.mc[.FF]]]]

Probably a small correction will be enough (I did not check).
VideoUtils.cpp

Code: Select all

bool
IsVP8CodecString(const nsAString& aCodec)
{
  return aCodec.EqualsLiteral("vp8") ||
         aCodec.EqualsLiteral("vp8.0") ||
         StartsWith(NS_ConvertUTF16toUTF8(aCodec), "vp08");
}

bool
IsVP9CodecString(const nsAString& aCodec)
{
  return aCodec.EqualsLiteral("vp9") ||
         aCodec.EqualsLiteral("vp9.0") ||
         StartsWith(NS_ConvertUTF16toUTF8(aCodec), "vp09");
}

[Moonchild]

That makes a lot of sense. Of course Google in their player would be pushing the codec string format they wrote
I'm not entirely sure but it seems to me we should actually parse the entire string (at least the non-optional parts) if we're going to support this.

[RealityRipple]

Sokath, his eyes uncovered!


sorry, I've been holding in a shaka when the walls fell joke since wednesday.

[Moonchild]

Temba, his arms wide!

I welcome a good STTNG joke now and then

[Kris_88]

it seems to me we should actually parse the entire string (at least the non-optional parts) if we're going to support this.

It may make sense to import the ExtractVPXCodecDetails() function from the new FF. Unfortunately, I have no environment now to build PM, so I can not check anything.

[Moonchild]

FYI: Parsing RFC-6381 VPx codec strings will be included in v31.0. I've verified that it resolves this shaka player issue.

[Kris_88]

Thank you!

[gecezop]

The issue is that MSE-DASH doesn't seem to be working in this particular player/this version of the player

[gecezop]

The issue is that MSE-DASH doesn't seem to be working in this particular player/this version of the player

hope it will be fixed in next update

[Moonchild]

The issue here (updated codec identification) was already fixed with the milestone. There's no further work slated for the next version regarding this.