BBCiPlayerTV HTML5 broken (again!) in Firefox-52+

Vangelis forthnet northmedia1 at
Sat Jan 7 04:39:48 UTC 2017

{The "(again!)" part refers to a previous iPlayer bug 
I filed in the list back in September 2016. }

OS: Windows Vista SP2 32bit, with all MS updates 
(including Platform Update Supplement for Vista, i.e. KB KB2117917). 
Thus, the system has native H264/AAC decoding support 
(via WMF/MSE) for HTML5 MP4 video files.

BBC iPlayer TV HTML5 Requirements

1. As far as this bug is concerned, the 
following test page can be used:

The embedded Media Player is either the 
Flash one (AdobeHDS streams) or the 
HTML5 one (MPEG-DASH streams), 
depending on OS, browser version and 
browser plugin configuration. 
This test page is not geo-blocked (but separate 
streams exist for UK and non-UK clients), 
nor does it require a UK TV licence.
The browser behaviour in this test page 
is expected to be identical to the behaviour 
exhibited on the main BBC iPlayer TV site:

which is UK-only, requires a valid UK TV licence 
and (pretty soon) will also require a BBCid (login).


1. Use Firefox Developer Editon 52.0a2 
(any build of 52.0a2).
2. about:addons => Plugins => 
Shockwave Flash => Never Activate
(if Flash NPAPI is installed, else disregard)

Though not strictly required, also

about:addons => Plugins => 
Primetime Content Decryption Module => Never Activate

so we're sure H264/AAC decoding is 
delegated to system codecs...
3. Visit about:support to verify e10s is ON

Multiprocess Windows  1/1 (Enabled by user)

If it's OFF, visit about:preferences#general => Startup 
=> tick "Enable multi-process Firefox Developer Editon"

4. Restart DevEd-52.0a2
5. Visit

"We think this page has embedded the HTML5 player, as seen below:" 
should appear above embedded player.

6. Click the black/pink "PLAY" square; 
Expected behaviour: Video clip should start playing
Actual behaviour: Playback fails, player shows

Additional Info: 

1. Browser Console reports something along this line: 

Media resource blob: could not be decoded. 1 iframe.html

2.This bug is only present when e10s is turned ON:

Flash Player + e10sON = OK
Flash Player + e10sOFF = OK 

HTML5 Player + e10sON = NW (this bug)
HTML5 Player + e10sOFF = OK


Firefox Developer Edition

Last good: DevEd-51.0a2.win32[20161114004005], LAST of the 51.0a2 cycle
First bad: DevEd-52.0a2.win32[20161114043455], FIRST of the 52.0a2 cycle


So, the bad cs came upstream from the 52.0a1 codebase. 
Fortunately, I can still run 52.0a1 on Vista, so here it goes: 

m-c (52.0a1) repo: 

Last good: Nightly-52.0a1.en-US.win32[20161109030210]
First bad: Nightly-52.0a1.en-US.win32[20161110030211]


m-c (52.0a1) hourly win32 (tinderbox builds) repo:

Last good: Nightly-52.0a1.en-US.t-b.m-c.win32[1478705843=20161109073723]
First bad: Nightly-52.0a1.en-US.t-b.m-c.win32[1478705964=20161109073924]


m-i (52.0a1) repo: 

Last good: Nightly-52.0a1.en-US.t-b.m-i.win32[1478659139=20161108183859]
First bad: Nightly-52.0a1.en-US.t-b.m-c.win32[1478659822=20161108185022]


CULPRIT CHANGESETS (either one/both):

Tracking is also requested, because BBC iPlayer is a very 
popular media platform (in the UK and globally)

Firefox 50.1.0: unaffected
Firefox 51.0b12: unaffected
Firefox 52.0a2: affected
Firefox 53.0a1 : Can't test, because of OS deprecation; 
last build of 53.0a1 that can run on Vista and still has WMF 
support is 20161218030213; this is "affected"

Since v52.0 would be the last major version (in the ESR) 
channel) that would support Vista, I have a vested interest 
in this bug getting fixed as soon as possible.

I don't possess the necessary Bugzilla skills to file this properly, 
but I think I shall post a comment on bug 1315144 to alert 
the devs about this; they should know how to proceed further... 

A personal note: 

This is probably gonna be one of the last bugs I file; 
I am currently full of resentment and bitterness against 
Mozilla, who decided to copycat Google and put Vista 
on the same sinking boat as the much older XP. 
I have been following Firefox's development in the 
Nightly Channel (in this Vista SP2 old laptop) since 
v23.0a1 (buildID=20130424030917 still on disk..); 
countless daily threads read over at the mozillazine 
Firefox Builds forum, also countless Bugzilla bugs read, 
so it now kind of pains me to not be able to continue...

Installing Win7 on this old laptop or switching over to Linux is, 
at least for now, out of the picture... But the Mozilla Foundation 
said, among other things, that they could not afford 
(them being a multinational enterprise) the heavy cost 
of maintaining Vista support any longer; they know better; 
but, likewise, I can't currently afford the "heavy cost" of 
buying a new laptop (probably with Win10 that I dislike...) 
to continue Nightly testing...
So, to recap, 2 more weeks of 52.0a2 testing, one 
cycle of 52.0b testing and several months frozen on 
52.0ESR (with no testing there...) - and we Vista users 
should be thankful for that, too, because we were not 
cut-off altogether... Such is life...
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