No matter what I try, for a 10 MB 3gp video I am getting a 5 MB mp4 video that doesn't seem to have the same quality. I tried with 'libx264' for the video codec, I tried just a simple ffmpeg -i input.3gp output.mp4 I tried ffmpeg -i input.3gp -vcodec h264 -c:a aac output.mp4 ffmpeg -i input.mkv -c:v libx264 -c:a aac -map 0 out.I'm trying to get lossless conversion of 3gp to mp4 using ffmpeg. This is useful for retaining different languages and subtitles that might be in the original.

Use -map 0 to instruct ffmpeg to take all streams from the input file (see the FFmpeg Wiki for more info). In case your input file has more than one video, audio and subtitle stream, ffmpeg by default does not convert all of them. ffmpeg -i input.mkv -c:v libx264 -crf 23 -c:a libfdk_aac -b:a 384k out.mp4 This encoder is not available in the static builds, but can be obtained with the pre-packaged / Homebrew versions of ffmpeg. 5.1 sound), you need to use another AAC encoder ( libfdk_aac). If your audio stream is using multiple channels (e.g. Here, for example, 500 kBit/s: ffmpeg -i input.mkv -c:v libx264 -crf 23 …įfmpeg -i input.mkv -c:v libx264 -b:v 500k …įor audio, you can set the bit rate too, with -b:a. You can also set a certain bit rate, depending on which file size you want. Try values between 19 and 26 to see what fits best. Lower means better quality, but higher file size. Then, in the simplest case run: ffmpeg -i input.mkv -c:v libx264 -c:a aac out.mp4įor controlling video quality, set the crf parameter, which defaults to 23. For macOS, you can install FFmpeg through Homebrew.

For Windows and Linux, static builds are availabe from the homepage. Make sure you run the latest version of FFmpeg.

Ffmpeg convert mkv to mp4 audio aac