Does anyone know if this issue has been fixed for mp4 files?
For me it still seems to not be working, I have [sound:video.mp4] fields which work perfectly fine on the Windows and Android app, but doesn’t show up at all on the web app.
On a side note, does anyone know if the web app is open source? I have some coding experience, and could try to add/fix this feature myself.
I split you off to your own topic.
Can you give me a better sense of what you mean by that? Is there nothing on your card at all, or is it not playable?
Sorry, it is not.
Thanks for creating a new topic and thanks for answering! 
Is there nothing on your card at all, or is it not playable?
For context, my card has only [sound:xyz.mp4] on the front, no other html or text or anything, and just “xyz” on the back (if it’s relevant, these were all created using the Media Import 2 plugin). And, when I open a deck in the web app, nothing shows up at all on the front, and for the back of course I see the text “xyz” as expected. I tried looking at the source html to see if it’s maybe a video loading issue or something, but I don’t see anything there either (shown below)
Finally, I tried opening some shared decks which have mp4 video content in them and they also don’t work for me. For example, this shared deck uses mp4 videos for it’s animation Glasgow field. I checked the source html and again there is nothing where I expect the mp4 video to be (shown below).
and here’s the Back Template for that card:
<div style='font-family: time; color:#ebebe8; text-align:center;'>
<div display-type="interpret-syntax" class="wrapped-english">{{IPA}}{{Example}}</div></div>
<hr>
<div style='font-family: time; color:#00aaaa; text-align:center;'>
{{Meaning}}</div><hr>
<div style='font-family: time;text-align:center;'></div>
{{Sounds american}}
<div style='font-family: time;text-align:center;'></div>
{{Mr salas tip}}
<div style='font-family: time;text-align:center;'></div>
{{animation Glasgow}}
Sorry, it is not.
Oh, alright. And do you know if there’s some API to access the data stored on AnkiWeb?
I’m sorry I missed your response!
If both your mp4 video files and those other mp4 video files aren’t working, then I think the answer is that AnkiWeb doesn’t support mp4 video files – at least in [sound:...] tags. Have you tried displaying the video by other means?
You shouldn’t need to access AnkiWeb data through an API – it’s the same data you already have on your own devices.