0.8.4a digital encoded audio: unsteady volume, tone on G5
Posted: 07 Jan 2006 12:36
When using the "Digital encoded output" in vlc 0.8.4a, dolby digital and dts starts to vary in volume and tone. This is most noticable on bass-sounds like male voices but it affects all sounds, not just bass.
Forgive me for the silly explanation that follows but I don't know how to explain it in an other way
If a normal deep bass sound is ooooooommmmmmmpppphhh
Notice the continuos steady bass
the sound produced through the encoded output "stutters" and varies in tone (capitals = higher volume)
oooOOoomMMmmmMPpppHHh
Notice the raising of the volume
The raising actually is gradual but the lowering (going from O to o) is instant.
Silly explanation I know. I could probably record it though.
The audio doesn't lag or anything it's just isn't steady. It's as if someone turns the volume up slowly from normal to a bit louder, quickly turns the volume back to normal again and once more start to slowly turn the volume up. The "invisible person" does this about once per second.
Naturally it's very annoying, especially since normal "non-encoded" output sounds just fine.
To reproduce:
hook the optical output of the G5 up to a 5.1 reciever
play any file with ac3 or dts sound non-encoded so you can hear how it should sound
switch to encoded output and play the same ac3 or dts-sound again and listen to the variation in volume and tone, especially on bass sounds or male voices
It might help to crank the volume up a bit but you sould be able to hear it on really low volumes too as long as you know what you're listening for.
The same file works without change in volume in EyeTV using its encoded output so if you've got EyeTV you can compare its encoded output and verify that it doesn't "stutter" too.
vlc 0.8.4a Powermac G5 2x2GHz, 2GB ram, Ati radeon 9600 128MB, 5.1 surround though the optical output of the G5
Forgive me for the silly explanation that follows but I don't know how to explain it in an other way
If a normal deep bass sound is ooooooommmmmmmpppphhh
Notice the continuos steady bass
the sound produced through the encoded output "stutters" and varies in tone (capitals = higher volume)
oooOOoomMMmmmMPpppHHh
Notice the raising of the volume
The raising actually is gradual but the lowering (going from O to o) is instant.
Silly explanation I know. I could probably record it though.
The audio doesn't lag or anything it's just isn't steady. It's as if someone turns the volume up slowly from normal to a bit louder, quickly turns the volume back to normal again and once more start to slowly turn the volume up. The "invisible person" does this about once per second.
Naturally it's very annoying, especially since normal "non-encoded" output sounds just fine.
To reproduce:
hook the optical output of the G5 up to a 5.1 reciever
play any file with ac3 or dts sound non-encoded so you can hear how it should sound
switch to encoded output and play the same ac3 or dts-sound again and listen to the variation in volume and tone, especially on bass sounds or male voices
It might help to crank the volume up a bit but you sould be able to hear it on really low volumes too as long as you know what you're listening for.
The same file works without change in volume in EyeTV using its encoded output so if you've got EyeTV you can compare its encoded output and verify that it doesn't "stutter" too.
vlc 0.8.4a Powermac G5 2x2GHz, 2GB ram, Ati radeon 9600 128MB, 5.1 surround though the optical output of the G5