Converting m4a to ogg

[Arenlor]

I'd prefer a command line version if possible. Batch use would be best.

[nothingspecial]

Converting one lossy audio format to another will just result in a lossier file.

If you must, check out ffmpeg

To enable the best performance see here

[ron999]

Hi

ffmpeg will do the job.

When I look in the 'presets' folder of WinFF he uses these settings:-

ffmpeg -i input.m4a -acodec vorbis -aq 60 -vn -ac 2 output.ogg

But if you use this from the command line, or using the WinnFF gui, you'll lose any tags.

Personally I would just use SoundConverter for a job like this. It would try and retain the tags.
But if you want to use cli for your own reasons then that's fine. Develop a script to batch convert.

[nothingspecial]

Hi

ffmpeg will do the job.

When I look in the 'presets' folder of WinFF he uses these settings:-

ffmpeg -i input.m4a -acodec vorbis -aq 60 -vn -ac 2 output.ogg

But if you use this from the command line, or using the WinnFF gui, you'll lose any tags.

Personally I would just use SoundConverter for a job like this. It would try and retain the tags.
But if you want to use cli for your own reasons then that's fine. Develop a script to batch convert.

m4a will not work nice until you do what is outlined in the link I posted,

[Arenlor]

This is the script I made. Seems to work well enough. Note that because it uses rename it is Debian derivative specific.

#!/bin/bash
# m4a2ogg converts all m4a to ogg in a directory.
# Arenlor
for i in *.m4a
do
        ffmpeg -y -i "$i" "$i".wav
        oggenc -q10 "$i".wav
done
rename 's/m4a.ogg/ogg/g' *
rm *.wav
rm *.m4a
exit 0

[andrew.46]

Hi ron,

When I look in the 'presets' folder of WinFF he uses these settings:-

ffmpeg -i input.m4a -acodec vorbis -aq 60 -vn -ac 2 output.ogg

But if you use this from the command line, or using the WinnFF gui, you'll lose any tags.

Newer versions of FFmpeg have an option to preserve the meta tags:

andrew@skamandros~$ ffmpeg -h | grep 'map_meta_data'
[...]
-map_meta_data outfile:infile  set meta data information of outfile from infile

This would make the commandline:

ffmpeg -i input.m4a \
	-acodec vorbis -aq 60 -vn -ac 2 \
	-map_meta_data outfile.ogg:input.m4a \
	output.ogg

I have to admit that I have not used this option extensively but it has worked flawlessly on the half a dozen time I have used it. Thus I am not completely sure how many media types it will work with...

All the best,

Andrew

[ron999]

Hi Andrew
That's very interesting about ffmpeg's meta data.
My version of ffmpeg has the option too.

ron@ubuntu:~$ ffmpeg -h | grep 'map_meta_data'
FFmpeg version SVN-r19352-4:0.5+svn20090706-2ubuntu2, Copyright (c) 2000-2009 Fabrice Bellard, et al.
[...]
-map_meta_data outfile:infile set meta data information of outfile from infile

I tested it using this command:-

ffmpeg -i "03 - Flying.m4a" -acodec vorbis -aq 60 -vn -ac 2 -map_meta_data outfile.ogg:"03 - Flying.m4a" output.ogg

Then I analysed the output file with MediaInfo:-

General
Complete name : /home/ron/Desktop/output.ogg
Format : OGG
File size : 3.06 MiB
Duration : 2mn 15s
Overall bit rate : 189 Kbps

Audio
ID : 0 (0x0)
Format : Vorbis
Duration : 2mn 15s
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Resolution : 16 bits

It doesn't seem to be working, there's no tag information there.

When I converted the file using SoundConverter the tags seem intact:-

General
Complete name : /home/ron/Desktop/03 - Flying.ogg
Format : OGG
File size : 3.00 MiB
Duration : 2mn 15s
Overall bit rate : 186 Kbps
Album : Magical Mystery Tour
Track name : Flying
Performer : The Beatles
Genre : Rock/Classic Rock/Pop
Copyright : © 2009 EMI Records Ltd
Comment : Lavf52.31.0
COMPOSER : The Beatles

Audio
ID : 1317219419 (0x4E832C5B)
Format : Vorbis
Format settings, Floor : 1
Duration : 2mn 15s
Bit rate mode : Constant
Bit rate : 192 Kbps
Channel(s) : 2 channels
Sampling rate : 44.1 KHz
Resolution : 16 bits
Stream size : 3.10 MiB
Writing library : libVorbis 1.2 (UTC 2007-06-22)

So maybe ffmpeg's meta data option works for some types of files and not others, as you hinted.