I'm hosting this video : https://itype.techforge.com.au/assets/videos/repeated/WordRat.mp4.
It seems to work fine unless you happen to be on an IPad and plug the headphones in. With the headphones unplugged audio works normally. With headphones plugged in the audio cuts out.
To rule out the issue being caused by something on my server I'm also hosting https://itype.techforge.com.au/assets/videos/sample-mp4-file.mp4. The audio for this mp4 is perfect on the same IPad whether headphones are in or out.
I've also found http://techslides.com/demos/sample-videos/small.mp4 which has the same IPad + HeadPhones issue that I'm having with my mp4.
I'm guessing this has something to do with the audio codec, but I don't know enough to know exactly what's wrong or how to fix it.
Media info for the sample-mp4-file:
Codec: MPEG AAC Audio (mp4a) Type: Audio Channels: 3F2R/LFE Sample rate: 48000 Hz
Media info for the WordRat:
Codec: MPEG AAC Audio (mp4a) Language: English Type: Audio Sample rate: 48000 Hz Bits per sample: 16 Bitrate: 317 kb/s
The video that isn't working was produced using Adobe Animate and Adobe Media Encoder.
Any suggestions gratefully received.