[FFmpeg-user] MP4s (and M4As) for music

[Mark Filipak]

On 08/06/2025 14.26, Paul B Mahol wrote:
> On Sun, Jun 8, 2025 at 6:18 PM Mark Filipak <
> markfilipak.imdb-at-gmail.com at ffmpeg.org> wrote:
> 
>> On 08/06/2025 13.51, Paul B Mahol wrote:
>>> On Sun, Jun 8, 2025 at 5:42 PM Mark Filipak <
>>> markfilipak.imdb-at-gmail.com at ffmpeg.org> wrote:
>>>
>>>> ffmpeg^
>>>>     -i "c:\chapters.txt"^
>>>>     -i c:\01.WAV^
>>>>     -i c:\02.WAV^
>>>>     -i c:\03.WAV^
>>>>     -i c:\04.WAV^
>>>>     -i c:\05.WAV^
>>>>     -i c:\06.WAV^
>>>>     -i c:\07.WAV^
>>>>     -i c:\08.WAV^
>>>>     -filter_complex
>>>> "[1:0][2:0][3:0][4:0][5:0][6:0][7:0][8:0]concat=n=8:v=0:a=1[out]"^
>>>>     -map_metadata 0 -map "[out]"^
>>>>     -c aac -b:a 657.6k^
>>>>     "c:\Ashra, Belle Alliance [1980].m4a"
>>>>
>>>>
>>>> *****
>>>> The script above provoked this: "Too many bits 15269.442177 > 12288 per
>>>> frame requested, clamping to
>>>> max". Of course, I have no idea what that's about. Do you? "Too many
>> bits"?
>>>> *****
>>>>
>>>> How did FFmpeg (or AAC) compute "15269.442177 > 12288". What are those
>>>> numbers? Why does the
>>>> complaint say "bits ... per frame requested" when there's _no_video_,
>>>> _no_frames_?
>>> https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/aacenc.c#L1243
>>
>> Thank you, but I can't read that. Is there documentation in English?
>>
>> Can you tell me why FFmpeg (or AAC) says "15269.442177" when I submitted
>> "-b:a 657.6k"?
>>
> Because its bad encoder, failed to keep promise within its limits.

Do you ever encode music, Paul? If so, what do you use?