[FFmpeg-user] ffmpeg mux cause quality loss

[Wu, Mandy]

Hi,
I used below command to mux H264 video and AAC audio to a MP4 container format:
ffmpeg.exe -i video.h264 -i audio.aac -vcodec copy -acodec copy -absf aac_adtstoasc output.mp4

Then I found out value of PSNR of output.mp4 referring to video.h264 is only 30.62. It seems a pretty small number.
Can someone advise how to use ffmpeg to mux H264 and AAC without much quality loss? Thanks a lot!


Thanks,
Mandy