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

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.

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.

I did the same sort of test using the vorbiscomment to edit the metadata of a "virgin" track and the before and after stream data (decoded with oggdec) is identical (using cmp to compare them).

The reason why using a "virgin" track is necessary in step 1 above is because when I tried editing the metadata a second time, the audio stream was not changed. I don't know if this is because Rhythmbox didn't re-encode the audio the second time or if the encoding reached a "steady state" where further encoding no longer modified it. I don't know if that's even possible.

Hotmail: Trusted email with Microsoft’s powerful SPAM protection. Sign up now.

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]