Recorded videos report framerate to be 59.58 while they are at 29.8

[saurabytes]

I record videos the capture activity and then play them back which is ok. I wanna do some video manipulation based on their framerate but it won't work as most of the video report wrong frame rates. I am using Nexus 5 with 4.4.2 installed on it with latest grafika code.

[fadden]

Setting and getting the camera frame rate is a bit tricky. I didn't want to complicate Grafika with a bunch of code that I didn't understand especially well, so the app makes a half-hearted attempt to set the rate and doesn't try to determine and publish the actual value.

There's a good explanation of how to configure the camera for a specific rate here: http://stackoverflow.com/questions/22639336/#22645327

[saurabytes]

Setting the framerate isn't an issue. I set it as 30 and ideally its 30 only but while reading it back sometimes it reports the video is 59.something. Is there a way and APIs that i can use to read video frame rates, ideally MediaMetadataRetriever should do this job but theres no key for that. I m using ffmpeg to read the rate currently which isn't working reliably as they are not 59 for sure. Any idea?

[fadden]

I'm not sure how the frame rate reporting works within ffmpeg. Video generated by Android is variable frame rate. You can look at the presentation time stamps to determine the spacing between two frames, but there's no guarantee from the encoder that the output will have frames at regular intervals.

I'm told that, with recent versions of the ffmpeg command-line app, you can convert videos from variable-rate to fixed-rate with something like:

ffmpeg -i device-video.mp4 -c:v libx264 -qp:v 0 -coder 0 -r 60 -vsync 1 -preset:v ultrafast output.mp4

Somebody was using this to convert "screenrecord" output to fixed-rate 60fps. I don't know if this fits with your planned usage.

[fadden]

Marking closed as this seems to be an issue with ffmpeg's interaction with MediaCodec output, rather than an issue with Grafika.