folder batch convert eac3 to .m4a @128

[skylinekiller]

I am trying to batch convert a bunch of .eac3 files to .m4a @128. the folder name is
H:\Need to Encode\Doctor

Any help would be greatly appreciated

[sneaker]

pushd H:\Need to Encode\Doctor
for %%a in (*.eac3) do "c:\programs\ffmpeg\ffmpeg.exe" -i "%%~a" -c:a aac -b:a 128k -ac 2 "%%~na.m4a"

Needs ffmpeg, obviously.


(I set -ac 2 for stereo downmix which I assume you want at only 128 kbps)

[skylinekiller]

the eac3 audio track is already stereo. And this sounds stupid, but where do I paste that code into? Command Prompt, ffmpeg? Usually I go to command prompt and do one file at a time with eac3to

[sneaker]

That specific code was meant for a batch file (open Notepad, paste, save as "whatever.bat" and double-click it). You can also use it on the prompt without a batch file but then you have to change all double percent signs (%%) to single ones (%).

You can also use eac3to (with NeroAacEnc.exe):

for %%a in (*.eac3) do eac3to.exe "%%~a" "%%~na.m4a"

Just note that eac3to's eac3 decoder is a bit outdated and supports less eac3to files than ffmpeg. So if eac3to doesn't work try ffmpeg.

[skylinekiller]

This is what I have tried so far

pushd H:\Need to Encode\Doctor
for %%a in (*.eac3) do "C:\Program Files\ffmpeg\bin\ffmpeg.exe" -i "%%~a" -c:a aac -b:a 128k -c:a 2 "%%~na.m4a"

and

for %%a in (*.eac3) do "C:\Program Files\ffmpeg\bin\ffmpeg.exe" -i "%%~a" -c:a aac -b:a 128k -c:a 2 "%%~na.m4a"

my ffmpeg.exe is 64bit and located here C:\Program Files\ffmpeg\bin

Either one just quickly opens a dos prompt and closes

[skylinekiller]

hold on a second.. Ok, I am getting an error, please see the picture "unknown encoder '2'
[Attachment 45874 - Click to enlarge]

[sneaker]

Sorry, my bad.
-ac 2 is stereo downmix, not -c:a 2

[skylinekiller]

That seemed to work, thank you. Would you mind answering another question? If I am just converting 5.1 eac3 to a 5.1 m4a what would be the code? Is it possible to boost the audio like in Ripbot?

[sneaker]

If you leave out the "-ac x" part ffmpeg will not downmix (unless required by the encoder, e.g. mp3 will only encode to mono or stereo so 5.1 will be downmixed). -ac 6 would be 6 channels (usually 5.1).

Audio volume:
https://superuser.com/questions/323119/how-can-i-normalize-audio-using-ffmpeg
https://trac.ffmpeg.org/wiki/AudioVolume

[pandy]

Alternatively '-ac' may be skipped at all to not force ffmpeg to particular channel number, also audio bitrate should be corresponding to channel number (i would not recommend less than 64kbps per channel if native ffmpeg AAC encoder is used), sadly to say '-q:a' doesn't work well with native ffmpeg AAC encoder.

[skylinekiller]

When I do 5.1/6ch audio, I usually stick with 384.

So if I am converting an 5.1 EAC3 audio file to a 5.1 .m4a audio file, my code would look like this?

pushd H:\Need to Encode\Doctor
for %%a in (*.eac3) do "C:\Program Files\ffmpeg\bin\ffmpeg.exe" -i "%%~a" :a aac -b:a 384k -c:a 2 "%%~na.m4a"

is this correct

[sneaker]

No.
"-c:a" is selectiong the audio codec, e.g. "-c:a aac" is choosing the aac encoder. ("codec" "audio")
"-ac x" is audio channel mixing, e.g. "-ac 6" is 6 channel audio (5.1). ("audio" "channels")

[skylinekiller]

I see, let me give that a try