What video formats are compatible with the assets library?

Question

What video formats are compatible with the iPhone's assets library?

In other words, for what video formats will ALAssetsLibrary's videoAtPathIsCompatibleWithSavedPhotosAlbum return YES?

I can't seem to locate any information on this in the iPhone Reference Library.

Answer 1

No one has mentioned this yet, but it depends on the iPhone / iOS device. In making an app that tries to copy Flickr videos to the photo album, I was getting frustrated when I kept getting invalid data results on writeVideoAtPathToSavedPhotosAlbum: calls for a non-Retina iPhone.

I ran some videoAtPathIsCompatibleWithSavedPhotosAlbum tests on Flickr videos of various sizes, as requested in this question.

                                  iPhone        iPhone       iPad
                               (non-Retina)    (Retina)
6119419764_orig.mov
H.264, 1,920 x 1,080               NO             NO          NO
Linear PCM, 16 bit 
little-endian signed 
integer, 48000 Hz, 
Stereo (L R)
35.33 Mbit/s

6119419764_hd.mp4
AVC Coding, 1,280 x 720            NO             YES         YES
AAC, 44100 Hz, Stereo (L R)
2.15 Mbit/s

6119419764_site.mp4
AVC Coding, 640 x 360              NO             YES         YES
AAC, 44100 Hz, Stereo (L R)
833.71 kbit/s

6119419764_mobile.mp4
AVC Coding, 568 x 320              YES            YES         YES
AAC, 32000 Hz, Mono
775.14 kbit/s

6121206003_orig.mov
(Taken with iPhone 3Gs)           
H.264, 480 x 360                   YES            YES         YES
AAC, 44100 Hz, Mono
865.94 kbit/s
30 fps

6110638568_reformat.mov
H.264, 640 x 360                   YES            YES         YES
AAC, 44100 Hz, Mono
3.57 Mbit/s

Based on this limited testing, for a given format and device, it looks like size matters most. (For the current Flickr encoding methods and url scheme, mobile videos work on all iOS device photo albums, whereas hd and site videos only work on Retina iPhones and iPads.)

An interesting side note is that HD videos will play on non-retina iPhones with the MPMoviePlayerController -- you just can't save them to the photo album.

Answer 2

If you want a list of supported audio/video technologies, read the iOS Technology Overview, in particular the Media Layer (scroll down to where it says "Video Technologies").

The video technologies in iOS support the playback of movie files with the .mov, .mp4, .m4v, and .3gp filename extensions and using the following compression standards:

• H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second, Low-Complexity version of the H.264 Baseline Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats

• H.264 video, up to 768 Kbps, 320 by 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3 with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats

• MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats

• Numerous audio formats, including the ones listed in “Audio Technologies”

That's the reference information for the media frameworks in iOS.

Answer 3

I recently added a video export feature for the living photo burst of stills in my super-fast camera app SnappyCam Pro.

To cater for old and new devices alike, I ended up creating a few MPEG-4 "probe" videos, each with a single black frame, at a variety of 4:3 resolutions:

1. 320x240px
2. 640x480px
3. 960x720px
4. 1440x1080px

The four video files added just 12KB to the App Bundle.

By then iterating through each, with -[ALAssetsLibrary videoAtPathIsCompatibleWithSavedPhotosAlbum:], I was able to then work out which options are valid for the final Camera Roll video export.

Answer 4

If I had to guess, I might use the iPhone's own specifications as a guideline for testing:

Video formats supported: H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format