988594 - [Camera][Nexus4] Very slow to draw previews when swiping through Preview from Camera

Status: RESOLVED INVALID

(Core :: Graphics, defect)

Description

[Marcia Knous [:marcia]]

Buri, while running with the latest master.

Gaia   5ae2df02e30bda2ae04830d6e181ecf31ff38817
SourceStamp c69c55582faa
BuildID 20140326040202
Version 31.0a1

STR:
1. Take a series of pictures using the camera app.
2. Select the gallery preview to the left of the shutter button.
3. Observe the attached video. There is a hesitation as the picture content draws on the screen. It draws very slow from the top.

Expected: Seamless transition.

Video is here: http://youtu.be/hVy1f8uhBH0

Bug 987569 is related.

Comment 1

[Hema Koka [:hema]]

We need to trace whats going on here...mike, can you help here

Comment 2

[Mike Habicher [:mikeh] (high bugzilla latency)]

I'll take a look.

For future reference, we can get profiling data by:
# ./profile.sh start
# ./profile.sh capture

...and then loading the resulting data into http://people.mozilla.org/~bgirard/cleopatra/

Comment 3

[Mike Habicher [:mikeh] (high bugzilla latency)]

Further to comment 2, the profile has a relatively small capture buffer, so you should run the 'capture' step right after reproducing the problem.

Comment 4

[Mike Habicher [:mikeh] (high bugzilla latency)]

Trivial to confirm with:
- gecko: b2g-inbound:ef73445154cf
- gaia: master:786421ba46463a9bb2cb35fb67b2e5e3dad87b1f

Comment 5

[Mike Habicher [:mikeh] (high bugzilla latency)]

Attachment: hamachi-camera-preview-jank-profile.tar.gz [from profile.sh]

Comment 6

[Mike Habicher [:mikeh] (high bugzilla latency)]

Based on the profile, we're spending a large chunk of time (~400ms) in here:
http://mxr.mozilla.org/mozilla-central/source/image/src/RasterImage.cpp#2247

It looks like we're hitting this dispatch:
http://mxr.mozilla.org/mozilla-central/source/image/src/RasterImage.cpp#2298

Comment 7

[Mike Habicher [:mikeh] (high bugzilla latency)]

Hmm, maybe there is more to this than a core graphics problem. I just noticed in the logcat the following messages:

03-28 18:34:26.279  1029  1029 E GeckoConsole: [JavaScript Error: "TypeError: this.fit is null" {file: "app://camera.gaiamobile.org/js/main.js" line: 8857}]

03-28 18:34:26.389  1029  1029 E GeckoConsole: Content JS ERROR at app://camera.gaiamobile.org/js/main.js:8412 in displayImage: The thumbnail contained in the jpeg doesn't fitthe device screen. The full size image is rendered.This might cause out of memory errors

And also, the device is constantly churning out:

03-28 18:34:26.399   893   919 D HwcUtils: Skip layer
03-28 18:34:26.399   162  1061 E mm-camera: vfe_aecawb_stats_update: AWB_AEC stats not enabled


03-28 18:34:26.399   893   919 D HwcUtils: Skip layer
03-28 18:34:26.399   162  1061 E mm-camera: vfe_aecawb_stats_update: AWB_AEC stats not enabled

Comment 8

[Mike Habicher [:mikeh] (high bugzilla latency)]

Oh, and most importantly--when I see those errors in comment 7, the previews never appear! The Camera gallery stays grey (blank).

Comment 9

[Diego Marcos [:dmarcos]]

The full image is rendered instead of the preview. There are three problems:

1. The gallery is not reading the preview/thumbnail and always passes the full image to the media frame. I'm working on fixing that (bug 990630)

2. We're not setting the thumbnail size when starting the camera and the default is picked. In the case of the nexus 4 it doesn't cover the screen and the full image will be render in the preview/gallery

3. None of the thumbnail sizes provided by the camera fits the nexus 4 screen. We have to downscale the full image if we want to improve render performance

Thumbnail sizes available on Nexus 4:

"[{"height":288,"width":512},{"height":288,"width":480},{"height":288,"width":432},{"height":384,"width":512},{"height":288,"width":352},{"height":240,"width":320},{"height":144,"width":176},{"height":0,"width":0}]"

Comment 10

[Hema Koka [:hema]]

Diego - We need to get this bug addressed first (in your list of bugs)...can I get an eta please!

thanks
hema

Comment 11

[David Flanagan [:djf]]

I don't think we have to fix this on the nexus 4 since we're not shipping on that device. We can live with slow previews since that device is pretty fast to begin with.  But we can't live with this on other devices.

Note that there is a build-time configuration option in 1.3 that allows us to define what "big enough" means for thumbnails. I don't remember whether that got ported to the refactored version of the camera, but if so, there is a build-time config option that allows us to workaround the nexus 4 thumbnail issue.

Comment 12

[Hema Koka [:hema]]

Diego, please provide an update

Comment 13

[David Flanagan [:djf]]

Bug 990630 landed last night and will be uplifted to v1.4 today.  That bug fixes this issue on Hamachi. The nexus 4 still has the issue becase the firmware on that phone cannot produce an EXIF preview that is big enough, and we are forced to decode the full-size image in order to display anything.  This isn't such a big deal on the Nexus 4, however, because that phone is faster.

We should keep this bug open, but I don't think we need to block on fixing it in 1.4.

When we have a stable solution to the downsample-while-decoding problem we can transition to using that instead of relying on EXIF previews.  I'm talking about bug 854795 or the alternative solution that has been proposed. Hopefully we will be able to use that to get the images to display really quickly.

Comment 14

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee didn't login in Bugzilla in the last 7 months, so the assignee is being reset.

Comment 15

[BugBot [:suhaib / :marco/ :calixte]]

In the process of migrating remaining bugs to the new severity system, the severity for this bug cannot be automatically determined. Please retriage this bug using the new severity system.

Comment 16

[Gregory Pappas [:gregp]]

Closing old B2G bugs