1189811 - no sound for my .mkv video on FFOS 2.5 Nightly

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Gaia::Video, defect)

Description

[Thatoo]

User-Agent: Mozilla/5.0 (Mobile; rv:42.0) Gecko/42.0 Firefox/42.0

I wanted to play a. mkv video on my FFOS 2.5 Nightly Nexus 5 but I don't have any sound...
Type : video/x-matroska (i don't know if that help).

Comment 1

[Pi Wei Cheng [:piwei] (inactive)]

Could you maybe attach a sample video for us to try to reproduce the issue?

Comment 2

[Shally Li（leave from Mozilla）]

This bug can be repro on latest Flame v2.2/2.5 and Aries v2.5 by using a '.mkv' video.

Repro STR:
1. Copy a '.mkv' video (video type: x-matroska) into device storage.
2. Open video app and play this video.

Actual results: When this '.mkv' video is played, user can't hear any sound.
See attachment: Flame_v2.2.3gp and logcat_v2.2.txt.
Reproduce rate: 6/6


Note: 
My testing '.mkv' video has 1.09GB, so I can't upload it to bugzilla for reference.

Device: Flame KK 2.2 (Affected)
Build ID               20150805032505
Gaia Revision          f8b119ac30e97df991c97682ac4d4f9ca22e1793
Gaia Date              2015-07-31 13:20:55
Gecko Revision         https://hg.mozilla.org/releases/mozilla-b2g37_v2_2/rev/0c7a85251e10
Gecko Version          37.0
Device Name            flame
Firmware(Release)      4.4.2
Firmware(Incremental)  eng.cltbld.20150805.065842
Firmware Date          Wed Aug  5 06:58:54 EDT 2015
Firmware Version       v18D v4
Bootloader             L1TC000118D0

Device: Flame KK 2.5 (Affected)
Build ID               20150805150207
Gaia Revision          581de383687dc441a878d2c91a0167c6ec688fef
Gaia Date              2015-08-05 01:48:40
Gecko Revision         https://hg.mozilla.org/mozilla-central/rev/b12a261ee32e
Gecko Version          42.0a1
Device Name            flame
Firmware(Release)      4.4.2
Firmware(Incremental)  eng.cltbld.20150805.195702
Firmware Date          Wed Aug  5 19:57:12 EDT 2015
Firmware Version       v18D v4
Bootloader             L1TC000118D0

Device: Aries KK 2.5(Affected)
Build ID               20150804223818
Gaia Revision          c5425d9f1f5184731a59ed4bc99295acbde30390
Gaia Date              2015-08-04 16:09:19
Gecko Revision         https://hg.mozilla.org/mozilla-central/rev/f3b757156f69
Gecko Version          42.0a1
Device Name            aries
Firmware(Release)      4.4.2
Firmware(Incremental)  eng.worker.20150804.220057
Firmware Date          Tue Aug  4 22:01:05 UTC 2015
Bootloader             s1

Note: My testing '.mkv' video has 1.09GB, so I can't upload it to bugzilla for reference.

Comment 3

[Shally Li（leave from Mozilla）]

Attachment: Flame_v2.2.3gp

Comment 4

[Shally Li（leave from Mozilla）]

Attachment: logcat.txt

Comment 5

[William Hsu [:whsu]]

According to comment 2, switching the status to "NEW" is better.

Comment 6

[Thatoo]

I'm sorry to reply so late, I'm travelling around Asia and I don't access internet everywhere.
Do you still need my sample of video? I don't know how to extract a sample of a .mkv file...

Comment 7

[Pi Wei Cheng [:piwei] (inactive)]

Thatoo,

It's okay comment 2 already took care of what I wanted to do.

Comment 8

[No-Jun Park [:njpark]]

My understanding is that we don't formally support .mkv videos.  pinging :djf for confirmation.

Comment 9

[David Flanagan [:djf]]

DeviceStorage recognizes .mkv as a video format. But it is a container format, and support for the container does not guarantee that the codecs used for the contained audio and video data are supported. 

In this case, it sounds as if the reporter had a .mkv video where we supported the video codec but not the audio codec.  

MKV is not a format that we have any kind of active support for. We don't have any sample videos in that format, for example, so it doesn't get tested.  Still, if the video plays in Firefox desktop (without any plugins) then I'd expect it to play on FirefoxOS as well.

To go any further with this bug, we need a short sample video that reproduces the problem. Or, at a minimum, we need to know what audio codec is used in the reporter's video.

Also: this is not a Gaia issue. It is a platform-level media codec issue, I think.  Until we know what the codec is, we won't know whether this is actually a bug in our MKV support or is just an audio codec that we don't support.

Comment 10

[No-Jun Park [:njpark]]

Questions for Shally:
- Does the video play normally with the Firefox Browser?
- If above is true, could you create a dropbox or box.com account, upload it there, and give us the download link so we can check which audio codec it uses?

Comment 11

[Thatoo]

For me, the audio codec was AC-3 (ATSC A/52), so maybe that's the reason. I don't know if FFOS support this codec.

Comment 12

[Shally Li（leave from Mozilla）]

Hi No-Jun,

> Questions for Shally:
> - Does the video play normally with the Firefox Browser?

    I can't play this mkv video by Firefox Browser, only "Download" page prompts.

> - If above is true, could you create a dropbox or box.com account, upload it
> there, and give us the download link so we can check which audio codec it
> uses?

    I have uploaded the transformed '.mkv' video (this video also can repro this bug but can be played normally by KMP Player) about 95MB to "Baidu cloud", hope to help you.

URL: http://pan.baidu.com/s/1i3Ld4wd
Password: 3z33


Please let me know if you have any questions.

Comment 13

[No-Jun Park [:njpark]]

So according to Comment 9 and 12, since it doesn't play on the Firefox browser, (but I wonder whether the .mkv extension is accepted by the browser though), and other players can play it, it can be a feature request I suppose?

djf, I guess we don't support AC-3 audio codec?

Comment 14

[David Flanagan [:djf]]

No-Jun,

I don't know much at all about Gecko's audio and video support at the codec level. The media team in Taipei would know more, as would someone like Anthony Jones in the new zealand office. 

According to Wikipedia, AC-3 is dolby digital, a patent-encumbered codec that requires a license for decoders. If that is true, then we will probably never be able to support it and this bug can be resolved as WONTFIX.

  David