How to transcode a video to 16:9 format and vary the bit rate (and perhaps FPS)?

Question

Say I access a video from the photo library using UIImagePickerController and then I want to export it in a 16x9 format (eg 960x540, 1280x720, 1920x1080), but I want also to control the bit rate or frames-per-second or anything else that can help reduce the size of the exported video. What API do I need to use to accomplish these (at least) two or three dimensions (aspect ratio, bit rate, perhaps FPS)?

I can use (we already are using) AVAssetExportSession and could us presets like AVAssetExportPreset960x540 , AVAssetExportPreset1280x720 and AVAssetExportPreset1920x1080 to get the 16:9 aspect ratio (and to some degree to control the size as each of these yields differently sized exports). But I don't think I can simultaneously control things like bit rate and FPS. Do I have to go to aa different API?

On a related question, I see that AVAssetExportSession has the boolean property shouldOptimizeForNetworkUse which "indicates whether the movie should be optimized for network use" or not. What does this optimization consist of?

Answer 1

Have you ever tried using FFMPEG (Third Party library for this)

http://ffmpeg.org/