User:Vitrinekast/Checking out the media fragments URI: Difference between revisions

Revision as of 18:18, 8 November 2023

Example of a media fragment URI URL: http://www.example.org/video.ogv?t=60,100#t=20

Text below is from the Media Fragments URI 1.0 (basic)

The names and values can be arbitrary Unicode strings, encoded in UTF-8 and percent-encoded as per RFC 3986. Here are some examples of URIs with name-value pairs in the fragment component, to demonstrate the general structure:

* http://www.example.com/example.ogv#t=10,20
* http://www.example.com/example.ogv#track=audio&t=10,20
* http://www.example.com/example.ogv#id=Cap%C3%ADtulo%202

Media fragment URI can be used on video, images, and audio(?) → altough mentioned in the spec as video only(?) but what is a video anyway...

Used on image

Following URL should show a cropped image, but it does not appear to work onchrome.

http://placekitten.com/500#xywh=percent:5,25,50,50

https://caniuse.com mentions that all browsers that have implemented something of this spec, have actually only implemented support for the #t=n,n control for selecting a range of video, and possibly track=(name) & id=(name).

Used in Audio!

I've uploaded some files to chopchop to test with

The following URL should only play the video from 00:01 to 00:02!

https://hub.xpub.nl/chopchop/~vitrinekast/videos/small.ogv#t=1,2

And... For mp3 it seems to work as wel!!

https://hub.xpub.nl/chopchop/~vitrinekast/videos/small.mp3#t=1,2

However, it does seem to fully load the file, when inspecting the request, which does not save any data being downloaded. However 2: when throttling the request to slow3g, only 277 bytes are being downloaded according to the network tab. Something to investigate further.

Check with charles to see if the amount of bytes are actually correct, as a reduced amount of bytes downloaded could be a positive result of using this to interact with an archive
However, in terms of radio, m3u8 files are already broadcasted in "blobs" → so maybe this is more relevant to look into

Further checking and reading the spec

A glossary from the spec

Media fragments support addressing the media along two dimensions (in the basic version):

temporal This dimension denotes a specific time range in the original media, such as "starting at second 10, continuing until second 20";

spatial this dimension denotes a specific range of pixels in the original media, such as "a rectangle with size (100,100) with its top-left at coordinate (10,10)";

Media fragments support also addressing the media along two additional dimensions (in the advanced version defined in [Media Fragments 1.0 URI (advanced)](https://www.w3.org/TR/media-frags/#mf-advanced)):

track this dimension denotes one or more tracks in the original media, such as "the english audio and the video track";

id this dimension denotes a named temporal fragment within the original media, such as "chapter 2", and can be seen as a convenient way of specifying a temporal fragment.

Spatial Dimension does not seem to work in chrome → clipping the video frame
I'm not entirely sure yet what id/track should do, and also how to set this metadata, if it is even metadata?

I tested https://hub.xpub.nl/chopchop/~vitrinekast/videos/small.mp4#track=audio but this still loads the full video instead of only the audio track. That could be great otherwise for the archive.

next steps

- [ ] Furher understand the Media fragment URI and what the current state of the spec is - [ ] Read about [OggKate - XiphWiki](https://wiki.xiph.org/OggKate) an open source codec which could be used for Karaoke, but essentially allows for attaching time based metadata (see example below)

 event {
   00:18:30,000 --> 00:22:50,000
   meta "GEO_LOCATION" = "35.42; 139.42"
   meta "DATE" = "2011-08-12"
 }

@@ Line 62: / Line 62: @@
-### next steps
+==next steps==
 - [ ] Furher understand the Media fragment URI and what the current state of the spec is
 - [ ] Read about [OggKate - XiphWiki](https://wiki.xiph.org/OggKate) an open source codec which could be used for Karaoke, but essentially allows for attaching time based metadata (see example below)