Timed_id3 data

[Wild Willy]

I have encountered timed_id3 data a number of times. You can use the string "timed_id3"
as a search key in this forum to find a number of those instances. Most recently, I
stumbled across them in this thread:

https://groups.google.com/g/video-downloadhelper-q-and-a/c/QvQ6r5pozdU

There is a reference in there to a Danish TV newscast. I ran that video's master
manifest through ffprobe & found every program identified in the manifest included a
stream identified as timed_id3. I have been trying to figure out what this stuff is.
When I run ffprobe on any manifest that includes timed_id3 streams, I get an error
message saying that ffprobe couldn't find a codec for the stream. When I try to download
any program containing a timed_id3 stream using ffmpeg, it simply ignores the stream.
Apparently, VDH has taken to doing that now as well, which is an improvement over what it
used to do, which was simply fail to download the content.

I have managed to stumble upon a web site called id3.org. The site has not been updated
since 2012 so I have my suspicions about just how current this timed_id3 technology is.
In any case, id3 data appears to have been originally conceived as metadata for
attachment to audio content. The ideas put forward on the site suggest that id3 data is
appropriate for such things as title, track number, composer, performer, karaoke-style
lyrics, factoids to display during playback, album cover art, and whatever the author
might care to imagine adding to his content. The implicit other half of the story is
that you need to have a media player that can recognize & display the timed_id3 data.
But the site mentions only MP3. The Danish site gives MP4. It's a TV broadcast, not
just audio but video as well. I'm guessing the timed_id3 data here is meant to be Danish
subtitles for hearing-impaired viewers. The web site seems very finnicky. I can visit
it & the video plays. But the next day, it won't play unless I clear all that site's
cookies out of Firefox. It seems like the site allows playing an item, this one anyway,
only once. If I want to play it again, I have to clear the cookies again. Once I manage
to get the video playing in Firefox, I am able to see a small equal sign in the usual
tool strip that hovers up on mouse movement. Clicking the = toggles visible Danish
captions on & off. I have to assume that's what is in the timed_id3 data.

The id3.org web site claims that VLC supports timed_id3 data. So I used VDH to find the
media manifest for this TV broadcast. Then I fed the URL of that media manifest into VLC
in the Open Network Stream menu selection. It played the broadcast just fine but there
was no evidence of the timed_id3 stream. Opening the object's properties from the VLC
Playlist showed only the expected video & audio streams, no id3 stream. Typing the v
command into VLC, which normally cylces through whatever caption/subtitle tracks there
may be, said there was no subtitle track. I visited the VLC Wiki site & searched for
id3. I got no useful help. They reinforce the idea that id3 data is for MP3 files.
They say you can change the id3 metadata in the Properies dialog that I already popped up
from the VLC Playlist. Not useful. I played an online stream in VLC, a stream that I
KNOW contains timed_id3 data. VLC didn't detect the data. Granted, it wasn't MP3 input,
rather it was MP4. But still. It seems that they aren't aware that id3 data is not
restricted to MP3 objects.

Of course, I tried looking in the ffmpeg documentation that comes with the ffmpeg
package. Of course, I found no mention of timed_id3. I did find some instances of id3
but they were all focused on processing the data during muxing/demuxing of one file into
another. I have to admit I don't entirely understand what muxing is. There certainly
was nothing that said, "Here's what you need to do to get ffmpeg to recognize & download
FROM THE INTERNET any stream data identified as timed_id3." Web searches on the subject
are singularly irrelevant to what I want to do. Everything I read was from people who
already know what id3 data is & they wanted to add it to their content. Nobody seems to
be focused on the simple END USER-ORIENTED task of simply playing the stuff. These
people all seem to be quite inwardly focused on their geeky little pursuits without any
consideration of less technical users actually using what they're making.

If anybody can tell me in plain user-oriented language how to download & display
timed_id3 data, I'd love to hear it. What tools are there that play this stuff back,
other than web sites specially tailored to deal with their own content? How do ordinary
users download & play back timed_id3 data? VDH doesn't do it. Ffmpeg doesn't do it.
What does?

[Maximillium]

https://aomediacodec.github.io/id3-emsg/

https://duckduckgo.com/?t=ffsb&q=timed_id3&ia=web

But I don't understand it - got my own problems with a spreadsheet....

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[Wild Willy]

Thanks for looking at this, Max. That information isn't really end user-oriented. It's
programming specifications aimed at programmers who are going to write code to . . . I
guess put timed_id3 data into a media file. That's most assuredly not what I'm looking
for. I'm looking for an application that an ordinary user who isn't trying to write any
kind of code can use. This application will take the URL of some media, including
possibly the URL of a manifest, & download the media WITH its timed_id3 data. Then I
want a second application that will play that media while recognizing the timed_id3 data
& displaying it . . . or doing whatever is appropriate with it. Since I have not yet
seen timed_id3 data getting downloaded onto my system, I don't know what it's supposed to
look like. Like I've been saying, I can see from ffprobe output that certain manifests
include streams of timed_id3 data. But ffprobe says it can't find a codec for it, ffmpeg
ignores it, & I've discovered in the past couple of days that VDH now also ignores it.
As far as I can tell, VLC also ignores it when the input media is other than MP3. So
above, when I talk about media being downloaded, I'm talking at least about MP4, MKV, &
WEBM (those are the ones I can think of, I'm sure there's more) that contain VIDEO as
well as audio content. The first reference you give also points to id3.org, which I had
already found, & like I said before, that site seems to imply that timed_id3 data is only
for MP3 media. But I've seen timed_id3 streams in media that include video. There seems
to be a blind spot. Sites exist on the web, I've visited them, other users here have
posted about problems on them, where there is VIDEO media containing timed_id3 data. The
standard doesn't seem to understand that. Maybe the problem is that web devs have
started using timed_id3 data in a way that is proprietary to their sites & doesn't really
adhere to the standard, assuming the standard is truly recognized as such. Maybe that's
why ffmpeg & VLC don't seem to be able to process timed_id3 data in VIDEO media. I
haven't actually come across any audio-only examples that include timed_id3 data. The
vast majority of the activity in this forum is from users getting video content. The
handful of folks who have posted about audio-only media don't appear to have encountered
examples that included timed_id3 data. There were a couple of examples within the past
few weeks of problems on audio-only sites that had me discovering DASH manifests (.mpd)
for those cases. But my ffprobes on those DASH manifests didn't turn up any timed_id3
data.

So in general, my mystery remains intact.

[Maximillium]

I agree with you about it all - just wanted to insert some definition of "timed_id3" to answer basic questions like "what is it?" and "what does it do?".

Surely someone on this list who is a programmer could tell us more about it ... unless their's is working fine and they're not tuning in.

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