[FFmpeg-user] ISSUE ABOUT libmp3lame AUDIO CODEC

Ferdi Scholten ferdi at sttc-nlp.nl
Thu Feb 29 19:37:37 EET 2024

Here are the technical infos about the source movie (the file that will 
be processed), infos provided by VLC MEDIA PLAYER :
> audio stream :
>       Codec: A52 Audio (aka AC3) (a52 )
>       Language: French
>       Description: AC3-5.1-VFQ
>       Sample rate: 48000 Hz
> and here is the command line I use :
>       ffmpeg.exe -loglevel error -sn -i "D:\temp\source movie.mkv" -map 0:v:0 -map 0:a:0 -acodec libmp3lame -ar 48k -b:a 128k -q:a 3 -vcodec libx265 -vf "scale=iw*2/5:ih*2/5" -sws_flags lanczos+accurate_rnd -b:v 1200k -minrate 1200k -maxrate 1200k -r 23976215/1000000 -qscale:v 2 -x265-params "nal-hrd=cbr:force-cfr=1:vbv-maxrate=1200:vbv-bufsize=2400"  -log_level -1 "C:\temp\re-encoded movie.mkv" -bufsize 2457600
> Is this because my command line is missing some parameters, and if so, which ones ?
You are transcoding a 6 channel audio stream (AC3 5.1) to a 2 channel 
audio stream (MP3) without specifying how to downmix the channels.
Please read and understand this documentation: 

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