|Open||None||T166024 Once it's not patent-encumbered, enable MPEG-2 support for Commons uploads and TMH/etc. playback|
|Stalled||None||T166025 Once it's not patent-encumbered, enable AAC-LC support for Commons uploads and TMH/etc. playback|
- Mentioned In
- T101716: Support MJPEG & PCM audio as last-ditch fallback output for iOS
D994: Run .mpg and .mpeg files through the video/ffmpeg processor
T167815: Conduct MP3 patrol discussion
T166025: Once it's not patent-encumbered, enable AAC-LC support for Commons uploads and TMH/etc. playback
- Mentioned Here
- T120288: Enable MP3 uploads on Wikimedia Commons and TMH playback
This task first needs to answer, in which file format it wants to support the codec. Codec detection happens in the file format parsing, so for each file format you want the codec to be supported in, you will have to take separate technical steps on that level (and thus likely separate tickets).
So far so good with the spike patch, except that some files I've tested don't detect the audio track, possibly some incomplete support in getid3. It also returns the wrong pixel aspect ratio for MPEG-2 video, which I was able to work around on the TMH end for now.
(Note that I believe standard .mpg and .mpeg files are in fact program streams, not transport streams, which is used for broadcast and some of the streams for Apple's HLS.)
Most browsers don't play MPEG-2 in <video> tags (Safari on Mac does, but not on iOS) and ogv.js doesn't yet include MPEG playback, so during the time between initial upload and the completion of the first transcode, users may see an ugly message about unsupported formats instead of it trying to play back the original source. Will want eventually to rethink the UI around transcoding status reporting on the File: page!
Question: is there any concern about extra patrolling needs for piracy in the case of decrypted DVD rips? Or would the large original size of full-length movies in MPEG-2 make this too difficult for drive-by uploaders to exploit?
Upstream issues reported:
- https://github.com/JamesHeinrich/getID3/issues/148 - aspect ratio on MPEG-2
- https://github.com/JamesHeinrich/getID3/issues/149 - missing audio track info on some files
If you are concerned of DVD rips, these used to be either the full .iso's rips, or they were the VIDEO_TS folders within them. VIDEO_TS is a structure around mpeg-ps files that includes the DVD metadata etc. BTW. DVDs are kinda special, if you'd play their raw files then likely you wouldn't enjoy the movie much, as they are divided in chapters, and sometimes this is quite messy. You really actually need that DVD specific metadata.
The most common format is MPEG-TS these days (used for DVB-C, DVB-T and DVB-S). MPEG-TS is a super flexible, timing accurate and streaming capable file format, that can basically include whatever you want. It supports hundreds of different type of codecs and metadata (EPG, chapters, menu's, subtitles, teletext etc).
I always say that MPEG-TS is what satellite engineers understood about writing specifications, that the Internet part of the world only understood just a few years ago. It's as flexible as mov/mp4/mkv, but with slight overhead, simply better manageable for the hardware industry.
Honestly, MPEG-PS is rare. It exists, but not nearly as much as you'd expect. DVDs are a super spec on top of it, or they are transcoded to simpler codecs, Broadcast video is MPEG-TS or ripped to other formats, and archived material is either the original captured video in camera specific formats, MXF or proprietary stuff around MPEG-TS.
I wonder if there is much matroska wrapped mpeg2 video...
I didn't have any MPEG-TS files handy but I did a quick test creating one with ffmpeg -- ffmpeg will take it as input and convert it just fine, but getid3's handling is incomplete and it errors out.
To support TS as well as PS, would need:
- complete the logic in getid3's module.audio-video.ts.php and patch it upstream
- (or replace with shell-out to ffprobe)
- make sure the mime detection maps .ts/.tsv/.tsa files to video/mp2t and does the correct magic check
- route the file handler class appropriately
- validate codecs so we don't let streams with MPEG-4, H.264 etc through
Note that for WMF production I think we'd also need to change our thumbor configuration to make sure the files get passed through the ffmpeg handler:
I don't think anything special would need to be added other than adding checks for the '.mpg' and '.mpeg' extensions.