AACs halt playback

chasedub · Post by **chasedub** » Tue Apr 10, 2007 4:20 pm

After I play an AAC file, the Play Queue will just halt. I have to manually double-click on the next file to start it. Example:

funkytown.mp3
dosed.mp3
bad medicine.m4a
dry your eyes.m4a
happier.mp3
goodnight moon.flac
maybe i'm amazed.mp3

It will play 1, then move onto 2, then stop.
If I double-click 3, it plays 3, then stops.
So I double-click 4, and it plays, then stops.
Then I double-click 5, and it plays, and continues normally onto 6 and 7.

I am only having this problem with AACs, and it seems to happen about 95% of the time. I suspected it might be a problem with the files, but I've seen it work and then not work with the same pairs of files, so I'm at a loss.

Has anybody else experienced this? If not, maybe I've just got a corrupt AAC decoder...

(By the way, this has been happening for a while, but I just tested it in the April 9 build.)

Post by **sbooth** » Sun Apr 22, 2007 2:59 pm

Do the files have different audio formats (sample rates, channels, etc.)?

I think there may be an issue where the queue does not auto-advance to songs that don't have the same (decoded PCM) format.

chasedub · Post by **chasedub** » Sun Apr 22, 2007 4:06 pm

I thought/hoped that might be the case, but the problem occurs even between tracks from the same album (which were ripped at the same time with the same settings). Just reproduced it in build 632.

(Speaking of build 632, I'm glad to see the split-screen Queue view -- great solution!)

Post by **sbooth** » Sun Apr 22, 2007 11:26 pm

Please try r638 and see if the problem is fixed- I believe it is.

chasedub · Post by **chasedub** » Mon Apr 23, 2007 12:25 am

638 works like a charm. I'm curious to know what the problem was, if it's not too obtuse... but even if you don't get the chance to explain it, Play is still (and increasingly) my favourite player.

Thank you!

Post by **sbooth** » Mon Apr 23, 2007 2:05 am

The problem was a little bit down in the weeds, but basically, Play decodes each type of file to the most accurate PCM representation possible. For MP3s it uses 24-bit PCM, AAC/Vorbis 16-bit PCM, and lossless it uses the native bit depth. True gapless playback can only occur when the two PCM formats are identical (in bit-depth, sample rate, endian-ness, et al). So, for the case where the PCM formats were not identical, the player was rejecting the next stream handed to it. The level above the player needed to manually set the next stream when the current stream's playback was complete, which it did incorrectly.

Paul Gotch · Post by **Paul Gotch** » Mon Apr 23, 2007 8:12 pm

sbooth wrote:True gapless playback can only occur when the two PCM formats are identical (in bit-depth, sample rate, endian-ness, et al).

Will play be able to play AAC pseudo gapless like iTunes? At the moment there appears to be a gap. I know that AAC is not really a gapless format and that iTunes puts an extra header in the AAC file to tell it how many frames at the end of the decode to ignore. Can Play read this header or is it difficult?