Android MediaCodec: encoding videos with resolution not divisible by 16 to codec other than H.264 and H.265

[antonlyap]

Current behavior:
When trying to encode a video with a resolution not divisible by 16 (e.g. 1080p) with Android MediaCodec, the resolution is aligned to 16 pixels (1920x1088). If the output is H.264 or H.265, this gets mitigated by cropping the stream with h264_metadata or hevc_metadata BSF.

How to reproduce:

% ffmpeg -i input.mkv -c:v vp9_mediacodec -b:v 4000k -c:a copy out.mkv # input.mkv is a 1080p video

% ffprobe out.mkv # displays 1920x1088

Proposed enhancement:
There are other methods to make sure that the output is 1920x1080 instead of 1920x1088:

• setting crop-bottom (and crop-right) on MediaFormat (​https://developer.android.com/reference/android/media/MediaFormat#KEY_CROP_BOTTOM). Unfortunately, it's only supported on API level 33+
• allowing the user to opt out of the alignment, as a lot of hardware can produce 1080p (or possibly other arbitrary resolution) output.

[antonlyap]

Also, it appears that we can get accurate info on alignment requirements on API 21+: ​https://developer.android.com/reference/android/media/MediaCodecInfo.VideoCapabilities.html#getWidthAlignment()

[quinkblack]

Replying to antonlyap:

Also, it appears that we can get accurate info on alignment requirements on API 21+: ​https://developer.android.com/reference/android/media/MediaCodecInfo.VideoCapabilities.html#getWidthAlignment()

Firstly, it's only available with the terrible designed Java API. Seconly, the information provided by this API on a lot of devides are incorrect, so it's not helpful if it's not reliable.

[quinkblack]

Fixed by 2a68b2d643f7b725defa9bec5174853a00411b98 and 7d46ab9e1206b09ebe1a94ecac49cc99d9b3522e