Re: [Rhythmbox-devel] editing metadata re-encodes audio?

[Jonathan Matthew <jonathan d14n org>]

In short, no. It re-muxes the encoded data, but it doesn't re-encode it.

What are you using to create the "virgin" tracks before you edit them?

On Tue, Feb 23, 2010 at 4:47 AM, Andrew Random <pseudo random live com> wrote:
> Version: Rhythmbox 0.12.5 on Ubuntu 9.10 64-bit
>
> To reproduce:
>
> 1. In Rhythmbox, rip a track from a CD to ogg vorbis format. To reproduce
> the problem you *must* start with a "virgin" track which has not previously
> had its metadata edited.
>
> 2. Make a backup copy of the resulting file.
>
> 3. In Rhythmbox, right-click on the track you ripped in step 1 and click
> Properties. Change the case of a single letter in the track title. Click
> Close to save the change.
>
> 4. Compare the size of the edited file to the backup copy you made in step
> 2. With the track I used, the new copy is 7727 bytes shorter than the
> original.

This sounds like the GStreamer oggmux plugin is either muxing the data
differently, or it's dropping some buffers (pages? packets?) somewhere
along the line.

> 5. Use a utility like ogginfo to view the stream info for both files. With
> the track I used, both the total data length and average bitrate are
> different.
>
> 6. Use a utility like oggdec to decode both files. With the track I used,
> the size of the decoded raw data differs by 47104 bytes.

If you open the output files in something like audacity, is the
re-muxed file missing some of the actual signal, or is it only silence
that's getting dropped?