what does this mean & why do i keep getting audio desync after re-encoding?

[corean]

hey guys, i need some help.

i record my gameplay with bandicam either with ut, lagarith or h264 cuda lossess and then i re-encode them to a smaller filesize usually with ripbot264
but my problem is, with my recoding mode set to 29.97 fps and pcm 44.1 stereo, i will always get an audio desync problem after i re-encode it. and it gets worse (the syncing problem) as the video plays longer. i dont know if its the video frame rate thats causing the problem or its the audio itself thats causing this.

this is my media info:

General
Complete name                    : G:\Action\BLR 2013-10-03 17-53-04-857.avi
Format                           : AVI
Format/Info                      : Audio Video Interleave
Format profile                   : OpenDML
File size                        : 2.90 GiB
Duration                         : 6mn 38s
Overall bit rate mode            : Variable
Overall bit rate                 : 62.5 Mbps
Writing application              : BandiAviMuxer 1.0

Video
ID                               : 0
Format                           : AVC
Format/Info                      : Advanced Video Codec
Format profile                   : Baseline@L3.2
Format settings, CABAC           : No
Format settings, ReFrames        : 1 frame
Codec ID                         : H264
Duration                         : 6mn 38s
Bit rate mode                    : Variable
Bit rate                         : 61.1 Mbps
Maximum bit rate                 : 20.0 Mbps
Width                            : 1 360 pixels
Height                           : 768 pixels
Display aspect ratio             : 16:9
Frame rate                       : 29.970 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 1.951
Stream size                      : 2.83 GiB (98%)

Audio
ID                               : 1
Format                           : PCM
Format settings, Endianness      : Little
Format settings, Sign            : Signed
Codec ID                         : 1
Duration                         : 6mn 38s
Bit rate mode                    : Constant
Bit rate                         : 1 411.2 Kbps
Channel(s)                       : 2 channels
Sampling rate                    : 44.1 KHz
Bit depth                        : 16 bits
Stream size                      : 67.0 MiB (2%)
Interleave, duration             : 10 ms (0.30 video frame)
Interleave, preload duration     : 39 ms

and specifically what does the last two lines mean?

Interleave, duration : 10 ms (0.30 video frame)
Interleave, preload duration : 39 ms

any help would be greatly appreciated! thanks in advance!

[Krispy Kritter]

Assuming the original doesn't have the issue, the problem is typically a result of the tool used.

[corean]

yes you are right. i switched to megui and re-encoded it. although there are still syncing problems, it definetly does help! thanks!

[jagabo]

Within media files the audio and video are usually interleaved. Ie, a little video, a little audio, a little video, a little audio... This is so the player can read a bit of video and audio, play them, then read the next bits, etc. without having to seek randomly within the file.

Interleave duration is the size of those audio chunks between the video chunks. Preload is how much audio appears before the first video chunk. These shouldn't cause A/V sync problems.

[El Heggunte]

........
i will always get an audio desync problem after i re-encode it. and it gets worse (the syncing problem) as the video plays longer. i dont know if its the video frame rate thats causing the problem or its the audio itself thats causing this.

and

yes you are right. i switched to megui and re-encoded it. although there are still syncing problems, it definetly does help!

Just in case the OP wasn't aware of this,

http://en.wikipedia.org/wiki/Gapless_playback#Compression_artifacts

However, my wild guess is, the original game recordings are out-of-synch already, and the re-encoding just makes the problem more obvious.

Ideally, game footage is best-recorded when:

a) it uses UN-compressed video or a lossless codec with very-low compression ratio ;

b) uses a different HDD ;

c) doesn't have to compete with other CPU-/memory-hungry applications (antivirus, useless services, etc) ;