Convert AVI to MP4 keeping the same quality
I'd like to convert a good amount of wmv, mpg and avi files (with differing audio and video encodings) to mp4/x264/aac with equivalent quality. I've done some tests with the following command:
ffmpeg.exe -i "test.avi" -c:v libx264 -c:a libvo_aacenc "test.mp4"
(As you can see, I've omitted options that specify the bitrate and quality of audio and video)
Using this command, FFmpeg automatically preserves the video dimensions, but I'm still not sure how it handles things like bitrate when they are omitted? What is the best way to keep the quality of a video while converting it to a different format and codec?
I'm using 64 bit Windows 7 and ffmpeg-20121230-git-518239c-win64-shared