javaandroidkotlinandroid-mediacodec

Android - Check if video file is .mp4. Convert it to .mp4 if not

In my app a user selects a video from their camera roll. I need to check if that video is in a .mp4 container format and if it is not, I need to convert it to .mp4.

Is there a modern way to do this today in Android?

Some of the things I tried:

I tried reading the mimeType from the File with String mimeType = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE). But I think this may not be accurate because I am not actually looking at the codecs in the file. The mimeType could be inaccurate.

It looks like people are saying to use ffmpeg to convert the file to .mp4, but the library listed is 7 years old and it seems overkill to use an external library for this. Is there a way modern way to do this with Android?

Solution

  • The MIME type reported by a MediaMetadataRetriever is usually correct. If it says video/mp4 then the container is likely MP4.

    You can double check it using a MediaExtractor:

    MediaExtractor extractor = new MediaExtractor();
extractor.setDataSource(context, fileUri, null);
PersistableBundle metrics = extractor.getMetrics();
String format = metrics.getString(MediaExtractor.MetricsConstants.FORMAT);
String mime = metrics.getString(MediaExtractor.MetricsConstants.MIME_TYPE);

    Note that this doesn't tell you what codecs were used to compress the video / audio tracks (H.264, H.265, etc.). For this you would need to look at the MIME type of the track.

    MediaFormat format = extractor.getTrackFormat(trackIndex);

    A low-code solution for transcoding is to use a library such as Media3 Transformer.