[3.2.x] Audio delay when playing videos with Stereo audio on Fire Stick 4K due to firmware bug
On the Fire Stick 4K, there is a slight but noticeable audio delay when playing videos with stereo audio. You have to add about 150ms to the audio when playing stereo files on the Fire Stick 4K. This is a result of a firmware bug in the Fire Stick 4K that affects VLC 3.2.6
Steps to reproduce:
- Use a Fire Stick 4K and make sure the Fire Stick 4K system settings are set to Settings > Audio > "Best Available" which is the default setting for audio playback.
- Play this test file on VLC 3.2.6 from the Amazon Store: https://fritschserver.no-ip.org/owncloud/index.php/s/lKDcKdo9GJNahYE
- Watch and listen to the impacts and their corresponding sounds. The impact sounds in the clip happen slightly after they are displayed on the screen.
- You can see the same delay on any video file with Stereo AAC audio. It's much more easily detected when viewing clips involving impacts.
- You can change the Fire Stick 4K system settings to Settings > Audio > Stereo to get rid of the delay, but then you have to keep changing it to get multichannel audio on multichannel files.
Players that DO NOT exhibit this issue:
- Nova Video Player hasn't had this issue in their latest version on the Amazon store due to a workaround.
- Kodi has just submitted a fix this for this issue, targeted for Matrix 19.0-alpha 1 here: https://forum.kodi.tv/showthread.php?tid=336151&pid=2931520#pid2931520 and https://github.com/xbmc/xbmc/pull/17504
Fritsch, the dev who fixed this on Kodi, left a message for @jbk and said to contact him via the email in this link if needed:
JB: If you read this: Implement the modern getTimeStamp API, keep the old GetHeadposition and use this value until Timestamp is stable, then switch over. Code you find in GetDelay method of AESinkAudioTrack - questions / suggestions welcome :-) VLC rocks.
I realize this issue is due more to the Fire Stick 4K's firmware than VLC, but this issue should be documented at the very least, if not worked around the way Nova and Kodi have done.