Given the 1.01.29a firmware, there is a problem with the Sansa Clip oggvorbis decoding that results in crackled audio on one or more output channels.
Shooting in the dark without a “real” scientific control variable, I will experiment…
Hypothesis [A]: Crackling audio is due to a particular vorbis encoder
Hypothesis [B]: Crackling audio is due to high/low bitrate
eshattow@zontar:/media/disk/MUSIC/BRC2008$ for i in *.ogg; do ogginfo “$i” > /tmp/vout/“$i”.log; done
eshattow@zontar:/tmp/vout$ grep libVorbis *| cut -d’:’ -f2- | cut -d’ ’ -f3- | sort | uniq
libVorbis I 20011231 (1.0 rc3)
libVorbis I 20020701
libVorbis I 20020717 (1.0)
libVorbis I 20020717 (GTune 3, beta 1)
libVorbis I 20030909 (1.0.1)
eshattow@zontar:/tmp/vout$ grep Nominal\ bitrate * | cut -d’:’ -f2- | sort | uniq
Nominal bitrate: 112.001000 kb/s
Nominal bitrate: 112.015000 kb/s
Nominal bitrate: 128.000000 kb/s
Nominal bitrate: 128.003000 kb/s
Nominal bitrate: 160.003000 kb/s
Nominal bitrate: 160.032000 kb/s
Nominal bitrate: 192.003000 kb/s
Nominal bitrate: 192.032000 kb/s
Nominal bitrate: 212.003000 kb/s
Nominal bitrate: 256.006000 kb/s
Nominal bitrate: 96.001000 kb/s
So, I can test 5 encodings briefly and incompletely.
20011231 (1.0 rc3): Fail (192kb/s); Pass (192kb/s); Pass (160kb/s) Pass (112kb/s)
20020701: Pass (96kb/s)
20020717 (1.0): Pass (256kb/s); Pass, I think… sample music was from glitch genre (192kb/s); Pass (160kb/s); Pass (128kb/s)
20020717 (GTune 3, beta 1): Pass (212kb/s); Pass (192kb/s)
2003090 (1.0): Pass (192kb/s)
The ogginfo output of a file that exhibits these crackles on the .29a firmware:
eshattow@zontar:/tmp$ ogginfo -v Radiohead\ -\ nice\ dream.ogg
Processing file “Radiohead - nice dream.ogg”…
New logical stream (#1, serial: 4d6f4e6b): type vorbis
Vorbis headers parsed for stream 1, information follows…
Version: 0
Vendor: Xiphophorus libVorbis I 20011231 (1.0 rc3)
Channels: 2
Rate: 44100
Nominal bitrate: 192.032000 kb/s
Upper bitrate not set
Lower bitrate not set
User comments section follows…
ALBUM=The Bends
ARTIST=Radiohead
DATE=1995
GENRE=Other
REPLAYGAIN_ALBUM_GAIN=-7.48 dB
REPLAYGAIN_ALBUM_PEAK=1.11347675
REPLAYGAIN_TRACK_GAIN=-5.81 dB
REPLAYGAIN_TRACK_PEAK=1.04714048
TITLE=(nice dream)
TRACKNUMBER=06
Vorbis stream 1:
Total data length: 5668416 bytes
Playback length: 3m:53.093s
Average bitrate: 194.545796 kb/s
Logical stream 1 ended
*Edit 2008-09-12* I found a file that is encoded with the rc3 libVorbis and at nominal 192kb/s rate which does pass the listening test. Weird stuff.
*Edit 2008-09-12* Also, I notice that the crackling happens mostly on the left channel with files that do not play properly. Disconnecting the left channel, the audio sounds (mostly) normal
Message Edited by lucent on 09-12-2008 06:42 PM