I'm working on Windows 10 x64, build ffmpeg-20180916-5109c38-win64-static.
I have a folder of MP3 audio files that I want to convert to M4A.
This is the command that I'm running:
FOR /F "tokens=*" %G IN ('dir /b *.mp3') DO ffmpeg -i "%G" -map_metadata 0 -c:a aac -b:a 192000 "%~nG.m4a"
This scans my bin filder and converts all files. This works great for converting video files from MOV to MP4 (using a different code string) but I keep getting errors such as:
[ipod @ 0000025507991b40] Frame rate very high for a muxer not efficiently supporting it.
Please consider specifying a lower framerate, a different muxer or -vsync 2
[libx264 @ 0000025507e45180] using SAR=1/1
[libx264 @ 0000025507e45180] MB rate (129960000) > level limit (16711680)
[libx264 @ 0000025507e45180] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0000025507e45180] profile High 4:4:4 Predictive, level 6.2, 4:4:4, 8-bit
[libx264 @ 0000025507e45180] 264 - core 157 r2932 303c484 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=4 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[ipod @ 0000025507991b40] Could not find tag for codec h264 in stream #0, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Error initializing output stream 0:1 --
[aac @ 0000025507e60100] Qavg: nan
Conversion failed!
What's the best way to convert to M4A? I'm doing this to reduce disk space.
Add -c:v copy. FFmpeg is trying to transcode the cover image. Although you shouldn't be getting that error even when transcoding - I'd consider that a bug.