slow motion video not playing in slow motion on no

2019-07-23 03:27发布

问题:

I'm able to record slow motion videos at 120fps using AVFoundation. These videos play as expected on iphone and mac quicktime player. But other players like videojs and my own player[AVPlayer] are not able to play it in slow motion. But if I create a slow motion video using iphone native camera app, then these same players are able to play it as expected.

I compared the two videos using mediainfo and two differences came up - 1. Format Profile: High@L5.1 vs High@L4.1 . I used ffpmeg to make my video's profile to High@L5.1 but it didn't make any difference.

  1. Format GOP : M=1, N=120 vs M=1, N=30. Again I used ffmpeg to set N=120 on my video but it didn't make any difference.

I also read online that exporting using PHAsset may help but my video files are created inside my Documents directory and will never go to Photo Album/Camera roll. I can probably try exporting to camera roll using PHAsset and then move it to my Documents directory as a hack (if it works at all). But I really need to know the underlying reason.

Any ideas what is causing this issue ? Thanks