audio sync problem

[vchampea]

I'm having audio sync problems with some files. I think it is only HD rips that are giving me sync problems. It seems to be in sync in the beginning, but then it falls out of sync later in the movie. I played the movie on my computer to see if it falls out of sync but it is in sync the whole time. I tried to play it again on the cinematube starting again from the beginning. I fast forward to the point where I was and it's out of sync again. I can't figure this out. The file I'm playing has AC-3 sound. I'm using toslink to connect to my 5.1 system.

[bVAdmin]

I'm having audio sync problems with some files. I think it is only HD rips that are giving me sync problems. It seems to be in sync in the beginning, but then it falls out of sync later in the movie. I played the movie on my computer to see if it falls out of sync but it is in sync the whole time. I tried to play it again on the cinematube starting again from the beginning. I fast forward to the point where I was and it's out of sync again. I can't figure this out. The file I'm playing has AC-3 sound. I'm using toslink to connect to my 5.1 system.

@vchampea Can you provide a MediaInfo dump of the file that you are trying to playback for analysis? When you are performing playback is this via a stream or via a HDD connected to your CinemaTube?

[vchampea]

Ok, here's the info:

General
CompleteName : C:\An Education.mp4
Format : MPEG-4
Format_Profile : Base Media
CodecID : isom
FileSize/String : 1.61 GiB
Duration/String : 1h 40mn
OverallBitRate/String : 2 308 Kbps
Encoded_Date : UTC 2010-06-18 23:11:30
Tagged_Date : UTC 2010-06-18 23:11:30
Encoded_Application : Yamb 2.1.0.0 [http://yamb.unite-video.com]

Video
ID/String : 1
Format : AVC
Format/Info : Advanced Video Codec
Format_Profile : High@L4.1
Format_Settings_CABAC/String : Yes
Format_Settings_RefFrames/String : 4 frames
CodecID : avc1
CodecID/Info : Advanced Video Coding
Duration/String : 1h 40mn
BitRate_Mode/String : Variable
BitRate/String : 1 857 Kbps
BitRate_Maximum/String : 7 677 Kbps
Width/String : 1 280 pixels
Height/String : 544 pixels
DisplayAspectRatio/String : 2.35:1
FrameRate_Mode/String : Constant
FrameRate/String : 23.976 fps
ColorSpace : YUV
ChromaSubsampling : 4:2:0
BitDepth/String : 8 bits
ScanType/String : Progressive
Bits-(Pixel*Frame) : 0.111
StreamSize/String : 1.30 GiB (80%)
Title : Imported with GPAC 0.4.6-DEV (build 1)
Encoded_Library/String : x264 core 67 r1145bm d2e1e1c
Encoded_Library_Settings : cabac=1 / ref=4 / deblock=1:-3:0 / analyse=0x3:0x133 / me=umh / subme=7 / psy_rd=0.0:0.0 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=2 / deadzone=21,11 / chroma_qp_offset=0 / threads=2 / thread_queue=2 / nr=0 / decimate=1 / mbaff=0 / bframes=3 / b_pyramid=1 / b_adapt=2 / b_bias=0 / direct=3 / wpredb=1 / keyint=250 / keyint_min=25 / scenecut=40 / rc=2pass / bitrate=1857 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
Encoded_Date : UTC 2010-03-13 23:47:40
Tagged_Date : UTC 2010-06-18 23:14:44

Audio
ID/String : 2
Format : AC-3
Format/Info : Audio Coding 3
Format_Settings_ModeExtension : CM (complete main)
CodecID : ac-3
Duration/String : 1h 40mn
BitRate_Mode/String : Constant
BitRate/String : 448 Kbps
Channel(s)/String : 6 channels
ChannelPositions : Front: L C R, Side: L R, LFE
SamplingRate/String : 48.0 KHz
BitDepth/String : 16 bits
StreamSize/String : 321 MiB (19%)
Encoded_Date : UTC 2010-06-18 23:13:20
Tagged_Date : UTC 2010-06-18 23:14:44

Sorry, that's a sloppy paste, but it's still readable. One guess I had is that the Bitrate for the audio is too high. The original audio was AAC but I'm using toslink so I converted it to AC-3. I set the bitrate to 448 Kbps, is that too high? The sample rate might be to high. It was set to 48000 hz. I'm playing the file from an external hard drive.

[bVAdmin]

@vchampea - Can you re-encode the audio at a lower bit rate to see if it resolves the audio synchronization issue? I would be very interested to hear your result.

[vchampea]

I looked at some of the other files I have on my hard drive. I have other movies that are 448 Kbps and 48000 hz. They play fine. But they were originally AAC. I only have trouble with the files that I had to convert from AAC to AC3. When I convert I use Yamb to get the AAC audio stream. Then I use Pavtube HD converter to convert that file from AAC to AC3. Then I use Yamb again to merge the file together. I read a little bit about Yamb. I've read that people always have audio sync problems. The weird thing is that when I play the files that were converted from AAC to AC3 they play fine on my computer with VLC Media Player. I have trouble when I try to play them on the cinematube. I'm going to look for some different programs to extract and join audio streams and see if that fixes my problem. I'll let you know what happens.