ffmpeg - multiline text in metadata (comment tag)

I use ffmpeg to update metadata tags like this way:

ffmpeg -i "in.m4a" -acodec copy -metadata artist="artist text"
-metadata comment="comment text" "out.m4a"

Well, "artist text" and "comment text" is usual plain text, but comment field allows to put multiline text. Each line must have new line character to do it. Something like this:

-metadata comment="source: lastfm \r\n tags: tag1, tag2 \r\n ..."

But all characters that I use (\r\n, %nl%, ^N) bring no result.

I run ffmpeg.exe from PHP script on Windows using shell_exec() function

Someone help please, or tell me is it really possible?...

You can do this with PowerShell using the `n for a newline and optionally `r for carriage return

ffmpeg -i in.m4a -metadata comment="hello`nworld" out.m4a

Windows default shell is cmd.exe so you may need to invoke like this

powershell ffmpeg -i in.m4a -metadata comment="hello`nworld" out.m4a

Output

Output #0, ipod, to 'out.m4a':
  Metadata:
    major_brand     : M4A
    minor_version   : 512
    compatible_brands: isomiso2
    comment         : hello
                    : world
    encoder         : Lavf55.1.100