An iPhone or camera MOV holds good audio inside a very large video file. Throw away the picture, keep just the part you want, and a 2 GB clip becomes a few megabytes. Choose the kind of recording, then set the start and end.
Open MP4, MKV, MOV, AVI, WMV, FLV, RealMedia, DVD VOB, camcorder MTS or almost anything else, and save it as any of 32 formats. The converting happens in this tab. Your video is never uploaded.
Each file is identified from its first bytes as soon as you add it. Once the engine is loaded it is read in full, so you see the real codecs, size and length before you convert.
MPEG-4 Part 14 on the ISO base media format. The safest choice when a file has to play anywhere.
ffmpeg -i input.mp4 -map 0:v:0 -map 0:a:0? -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -c:v libx264 -preset veryfast -crf 23 -pix_fmt yuv420p -c:a aac -b:a 128k -ac 2 -f mp4 -movflags +faststart video.mp4When QuickTime or a screen recorder captures a meeting or tutorial, the microphone and the system audio often end up as two tracks. Many converters keep only the first and silently lose the other. Set the balance before the tracks are mixed into one MP3.
Each fix removes a narrow band of sound. Leave them off for clean recordings, since every filter changes the tone a little. Turn one on to see the band it removes.
In a MOV, the audio is a thin stream beside a very thick video stream. Removing the video is where nearly all the saving comes from; the MP3 bitrate barely matters by comparison.
Neighbouring tools, with a typical result for each.