Multimedia June 2015

multimedia@lists.wikimedia.org

14 participants
7 discussions

Recommendations for tweaking media transcode settings
by Brion Vibber 27 Jun '15

27 Jun '15

I've been testing Ogg and WebM video playback on my various iOS devices <https://github.com/brion/OGVKit> in prep for adding playback support to the Wikipedia iOS app. Here's a few notes on our infrastructure: *Bandwidth* Bandwidth usage for 360p transcodes may be a bit tight for flaky 3G networks, but the only lighter transcode we have is a tiny tiny 160p. - Recommend adding a 240p transcode step with intermediate bandwidth. *Frame rate* 60fps/50fps source files get transcoded at the same framerate; this means limited bandwidth is spent on extra frames instead of picture quality, and 60fps playback can be heavy on CPU usage for slower computers and mobiles. - Recommend decimating >=48fps to half the frame rate on transcodes. Sometimes you want the 48/50/60fps, but usually it seems unnecessary and things are just being transcoded from high-quality source material. Examples of gratuitous 60fps: - https://commons.wikimedia.org/wiki/File:Wiki_Makes_Video_Intro_4_26.webm - https://commons.wikimedia.org/wiki/File:Hamilton_Mixtape_%2812_May_2009_liv… - https://commons.wikimedia.org/wiki/File:Big_Buck_Bunny_4K.webm *Seeking performance with Ogg audio* The Ogg format is kind of weird in that it's really designed more for live streaming than for encoding a fixed-length sequence. Part of that legacy is that by default, seeking to a particular time within a file requires doing a bisection search -- you jump around to byte positions in the file, sync up the decoder, and check if you have to go up or down. This is really hard on latency over the internet, especially on mobile networks or on far-flung continents. - Recommend transcoding/remuxing all Ogg audio and adding skeleton index. Ogg files can contain an optional index in a 'skeleton' track, which we include by default on all our Ogg Theora *video* transcodes -- this makes seeking much faster, as the player knows the byte positions of various times in the file to start with. Currently, TimedMediaHandler only produces Ogg transcodes if the original file was not Ogg Vorbis to begin with (eg, if it was a WAV file or Ogg using FLAC encoding or something). It should be easy to tweak that logic to always produce a transcode, and make sure we include skeleton tracks on audio output too. *API* The videoinfo query in the API can be used to get a list of transcodes, but it feels very icky to use, and of course is totally bound to MediaWiki. - Recommend exposing sources list as an MPEG-DASH manifest file that can be passed directly into a DASH-supporting WebM-supporting player. Need to research this one further; documentation seems wonky on the format. -- brion

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Upload tool strategy change
by Mark Holmquist 23 Jun '15

23 Jun '15

Hi, Multimedians. I've been talking with our new multimedia team, we're just getting to the point where we have a really good idea of where we want to go after a little while of doing work mostly on existing issues and refactoring efforts, and I have a small announcement to make. In the next few months, we intend to work on pulling upload API logic into core, and writing a new interface for uploading files from VisualEditor. Our initial plan involved refactoring UploadWizard to a point where including it in VisualEditor would not be difficult, but our new plans include usability improvements that, in my opinion, would unnecessarily enmire our work. Our team will be submitting patches to OOJS-UI, MediaWiki Core, and VisualEditor itself in an effort to get this project off the ground, as well as tweaking configuration settings in mw-config and generally running around looking for code review. Rest assured, we intend to maintain our commitment to fixing bugs in UploadWizard as they come up, as well as bugs in the myriad other Multimedia projects. Please continue to bother the Multimedia team if and when things go wrong, we are always happy to help you, or at least point you in the right direction. Here is a rough roadmap of where we need to go in the next few months: # mw.Api.plugin.upload API to automatically detect what methods are available for the browser, take a File object or file input, and perform the upload ## Base upload API with simple API call, quick and dirty, with gadget proof-of-concept https://phabricator.wikimedia.org/T103397?workflow=create ## Expand to use File API where available https://phabricator.wikimedia.org/T103398 ## Expand to support stashing with appropriate continue-upload API https://phabricator.wikimedia.org/T103399 ## {{stretch}} Expand to use chunked uploading where available https://phabricator.wikimedia.org/T103398 # Tie together all of those things into an Upload object or similar in core, so we can handle it with relative ease in our mostly-UI extension ## Create Upload model API in core https://phabricator.wikimedia.org/T103413 ### Base functionality - use the new upload API to upload a file, configurable to use stash ### Base functionality - finish stash upload ### Base functionality - set file description page text for upload (to be used in finish-stash call, or in initial upload if no stash option passed in) # Upload OOUI widget can then just use all of those things, and it can live in VE instead of having to be across a couple of extensions. ## Create upload widget in VE https://phabricator.wikimedia.org/T91717 {{epic}} ### Upload inspector ### File input widget in OOUI {{done}} ### Take file from widget, use upload API in core to stash ### Description/licensing/category form ### Emit finished upload from widget ## Use upload widget for inserting files into VE https://phabricator.wikimedia.org/T91717 (new task?) ### Add upload widget as above ### Use emitted file to construct thumbnail (file API?), caption (based on description) ## Drag-and-drop https://phabricator.wikimedia.org/T40031 ## Copy-paste https://phabricator.wikimedia.org/T39932 -- Mark Holmquist Lead Engineer, Multimedia Wikimedia Foundation mtraceur(a)member.fsf.org https://wikimediafoundation.org/wiki/User:MHolmquist

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WebM/Ogg playback: testing energy usage on iOS
by Brion Vibber 19 Jun '15

19 Jun '15

One of the reasons we've always worried about using the open Ogg and WebM formats on iPhones and iPads is that we don't get to make use of the hardware MP4/H.264 codec... using the main CPU cores is presumed to drain the battery faster. I've done a first-pass test measuring energy usage of native-code WebM/Ogg playback using the new energy reporting in the Xcode 7 / iOS 9 beta: https://brionv.com/log/2015/06/19/webm-and-ogg-energy-usage-on-ios-9-beta-w… The good news is that playback of buffered data at my target resolutions (360p for 32-bit, 720p for 64-bit) is barely under the "Low" mark on the energy drain meter! :D The bad news is that H.264 playback with the native widget reports post-buffer-download energy drain even lower, at the "Zero" mark... if you can believe that! (In both cases, reported drain is significantly higher during network download, at least on my fast wifi.) But "Low" sounds pretty good... If folks would like to see more concrete measures, I can rig up my test to run continuously until the battery runs out and time it. -- brion

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Audio/video updates: TimedMediaHandler, ogv.js, and mobile
by Brion Vibber 11 Jun '15

11 Jun '15

I've been passing the last few days feverishly working on audio/video stuff, cause it's been driving me nuts that it's not quite in working shape. TL;DR: Major fixes in the works for Android, Safari (iOS and Mac), and IE/Edge (Windows). Need testers and patch reviewers. *== ogv.js for Safari/IE/Edge ==* In recent versions of Safari, Internet Explorer, and Microsoft's upcoming Edge browser, there's still no default Ogg or WebM support *but* JavaScript has gotten fast enough to run an Ogg Theora/Vorbis decoder with CPU to spare for drawing and outputting sound in real time. The ogv.js decoder/player has been one of my fun projects for some time, and I think I'm finally happy with my TimedMediaHandler/MwEmbedPlayer integration patch <https://gerrit.wikimedia.org/r/#/c/165478/> for the desktop MediaWiki interface. I'll want to update it to work with Video.js later, but I'd love to get this version reviewed and deployed in the meantime. Please head over to https://ogvjs-testing.wmflabs.org/ in Safari 6.1+ or IE 10+ (or 'Project Spartan' on Windows 10 preview) and try it out! Particularly interested in cases where it doesn't work or messes up. *== Non-JavaScript fallback for iOS ==* I've found that Safari on iOS supports QuickTime movies with Motion-JPEG video and mu-law PCM audio <https://gerrit.wikimedia.org/r/#/c/217295/>. JPEG and PCM are, as it happens, old and not so much patented. \o/ As such this should work as a fallback for basic audio and video on older iPhones and iPads that can't run ogv.js well, or in web views in apps that use Apple's older web embedding APIs where JavaScript is slow (for example, Chrome for iOS). However these get really bad compression ratios, so to keep bandwidth down similar to the 360p Ogg and WebM versions I had to reduce quality and resolution significantly. Hold an iPhone at arm's length and it's maybe ok, but zoom full-screen on your iPad and you'll hate the giant blurry pixels! This should also provide a working basic audio/video experience in our Wikipedia iOS app, until such time as we integrate Ogg or WebM decoding natively into the app. Note that it seems tricky to bulk-run new transcodes on old files with TimedMediaHandler. I assume there's a convenient way to do it that I just haven't found in the extension maint scripts... *== In progress: mobile video fixes ==* Audio has worked on Android for a while -- the .ogg files show up in native <audio> elements and Just Work. But video has been often broken, with TimedMediaHandler's "popup transforms" reducing most video embeds into a thumbnail and a link to the original file -- which might play if WebM (not if Ogg Theora) but it might also be a 1080p original which you don't want to pull down on 3G! And neither audio nor video has worked on iOS. This patch <https://gerrit.wikimedia.org/r/#/c/217485/> adds a simple mobile target for TMH, which fixes the popup transforms to look better and actually work by loading up an embedded-size player with the appropriately playable transcodes (WebM, Ogg, and the MJPEG last-ditch fallback). ogv.js is used if available and necessary, for instance in iOS Safari when the CPU is fast enough. (Known to work only on 64-bit models.) *== Future: codec.js and WebM and OGVKit ==* For the future, I'm also working on extending ogv.js to support WebM <https://brionv.com/log/2015/06/07/im-in-ur-javascript-decoding-ur-webm/> for better quality (especially in high-motion scenes) -- once that stabilizes I'll rename the combined package codec.js. Performance of WebM is not yet good enough to deploy, and some features like seeking are still missing, but breaking out the codec modules means I can develop the codecs in parallel and keep the high-level player logic in common. Browser infrastructure improvements like SIMD, threading, and more GPU access should continue to make WebM decoding faster in the future as well. I'd also like to finish up my OGVKit package <https://github.com/brion/OGVKit> for iOS, so we can embed a basic audio/video player at full quality into the Wikipedia iOS app. This needs some more cleanup work still. Phew! Ok that's about it. -- brion

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Animated GIF players ?
by Derk-Jan Hartman 08 Jun '15

08 Jun '15

I added: https://phabricator.wikimedia.org/T101644 <https://phabricator.wikimedia.org/T101644> https://gerrit.wikimedia.org/r/#/c/216538/ <https://gerrit.wikimedia.org/r/#/c/216538/> It’s not much, but it’s something. What do you guys think, would something like this be useful ? DJ

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WebP uploads
by Derk-Jan Hartman 07 Jun '15

07 Jun '15

I have revived the WebP upload patch: https://gerrit.wikimedia.org/r/#/c/95872/ <https://gerrit.wikimedia.org/r/#/c/95872/> It’s been stale for like 2 years, but I think we can easily get this deployed. We would need a review by Chris perhaps It’s a bit incomplete in the metadata support, but we don’t really need that initially as far as I’m concerned. DJ

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flickrupload updates?
by Greg Grossmeier 04 Jun '15

04 Jun '15

Hi multimedia people! I was wondering if there was any post-hackathon follow up with the flickrupload work that happened? Anything interesting/fun coming down the pipe there? Greg -- | Greg Grossmeier GPG: B2FA 27B1 F7EB D327 6B8E | | identi.ca: @greg A18D 1138 8E47 FAC8 1C7D |

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Multimedia June 2015