# Video playback on mobile: can't seek to the end

My Unity3D game needs to play videos on mobile devices (using Handheld.PlayFullscreenMovie()). Seeking works badly. If I tap the video progress bar near the end (expecting it to play the last second then finish), playback jumps back a full 10-20 seconds, depending on the video. What should I try to make it easier for the player to seek within the file? Force additional key frames?

I'm currently encoding with HandbrakeCLI and the following settings:

--preset="AppleTV" --x264-tune=animation --x264-preset=veryslow


## 1 Answer

If you're using x264 encoding, your most likely problem is keyframes*. See this link and search for keyframe (it's the first thing there). Of course, you're not using FFmpeg, so you need the options for HandbrakeCLI, which seems to be "-x" command (a.k.a. --encopts) which receives a string, detailed here. Try those options out.

(--encopts "keyint=60" sets the maximum GOP size to 60 frames, which should make (at least) every 2 seconds searchable for a 30FPS video but that would also mean much lower compression)

*Keyframes are used for compression and you can only search between keyframes in a x264 compression (Jump from one keyframe to another). It is most likely a really high number by default for extreme compression.

• Thanks, that did it. But the option name has changed, and the syntax is wrong--HandbrakeCLI uses the same syntax for its long and short options. I hope you don't mind if I edit your answer. – piojo Dec 7 '16 at 3:01
• Yeah, it's cool. I don't really have any experience with HandlebrakeCLI, so your edit is more than welcome. – John Hamilton Dec 7 '16 at 5:33