Is it possible to transcode various of videos to H.264 as almost the same quality using FFmpeg?

1
votes

I have various of videos captured from various of resources but using different video/audio codec, bitrate and resolution.

Here's some example :

  • video: WMV3, bitrate: 6Mbps, audio: WMA, format: WMV
  • video: H.263, bitrate: 30Mbps, audio: MP3, format: AVI
  • video: H.264, bitrate: 20Mbps, audio: AAC, format: MKV

Actually the video resolution may different, but this is not the key point. There's quite a lot of videos make it really impossible to try the best video bitrate for each one.

So, Is it possible to convert all these videos to H.264 and AAC with MP4 format, and keep the same video quality as the original?

Or the problem maybe, is there a bitrate mapping between two audio or video codec, something like (I make it up, just a example) h.263 10Mbps ≈ h.264 6Mbps ?

1
videoffmpegtranscoding

1 Answers

3
votes

The libx264 encoder has a CRF rate control mode which, roughly speaking, does just this.

ffmpeg -i in -c:v libx264 -crf 23 -c:a copy out

Lower CRFs retain greater quality at a cost of larger file sizes. 18 to 28 is a decent range to stick within.