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Old 12th December 2010, 04:23   #1  |  Link
VelociRacer
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Join Date: Jul 2007
Location: Windsor-Detroit
Posts: 12
Audio Sync Issue

Over the course of the last 4 years, I've been converting our family video clips from Canon PowerShot A620 using AutoGK 2.55 Xvid 75% quality, auto video and audio settings. The resulting MPEG4 file has MP3 VBR audio.

GREAT! MPC-HC plays all my files flawless. I recently purchased a Seagate FreeAgent Theater+ HD medial player. I noticed that video plays choppy and lags behind the audio. After some experimenting, I finally got smooth video in perfect sync only when I encode with MP3 CBR audio (VBR was the culprit).

I noticed that when I open my AutoGK-created files using Avidemux I get 2 messages:

1-Avidemux detected VBR MP3 audion in this file. For keeping audio/video in sync, time map is needed. Build it now?
2-Index is not up to date. Rebuild frame now?


Despite clicking yes to both, FreeAgent plays only a second or two of the new file and stops. Maybe I'm not doing it right. It's my first day using Avidemux.

Sounds like from now on, I should select CBR to ensure better support with the FAT+. Since I have nearly 500 files with VBR. Is there a way to batch process them and fix this issue? Either converting VBR to CBR or rebuilding the avi files with time maps?

Here are Media Infos for a file before and after Avidemux changes:

RAW file
Code:
General
Complete name                    : E:\Temp\MVI_3249.AVI
Format                           : AVI
Format/Info                      : Audio Video Interleave
File size                        : 163 MiB
Duration                         : 1mn 31s
Overall bit rate                 : 15.0 Mbps
Mastered date                    : FRI DEC 03 13:45:52 2010
Writing application              : CanonMVI02

Video
ID                               : 0
Format                           : M-JPEG
Codec ID                         : MJPG
Duration                         : 1mn 31s
Bit rate                         : 14.9 Mbps
Width                            : 640 pixels
Height                           : 480 pixels
Display aspect ratio             : 4:3
Frame rate                       : 30.000 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 1.616
Stream size                      : 162 MiB (99%)

Audio
ID                               : 1
Format                           : PCM
Format settings, Sign            : Unsigned
Codec ID                         : 1
Codec ID/Hint                    : Microsoft
Duration                         : 1mn 31s
Bit rate mode                    : Constant
Bit rate                         : 88.2 Kbps
Channel(s)                       : 1 channel
Sampling rate                    : 11.024 KHz
Bit depth                        : 8 bits
Stream size                      : 982 KiB (1%)
Interleave, duration             : 991 ms (29.74 video frames)
Interleave, preload duration     : 1000 ms
After AutoGK
Code:
General
Complete name                    : E:\Temp\MVI_3249_agk1.avi
Format                           : AVI
Format/Info                      : Audio Video Interleave
File size                        : 46.1 MiB
Duration                         : 1mn 31s
Overall bit rate                 : 4 241 Kbps
Writing application              : VirtualDubMod 1.5.4.1 (build 2178/release)
Writing library                  : VirtualDubMod build 2178/release

Video
ID                               : 0
Format                           : MPEG-4 Visual
Format profile                   : Advanced Simple@L5
Format settings, BVOP            : Yes
Format settings, QPel            : No
Format settings, GMC             : No warppoints
Format settings, Matrix          : Custom
Codec ID                         : XVID
Codec ID/Hint                    : XviD
Duration                         : 1mn 31s
Bit rate                         : 4 175 Kbps
Width                            : 640 pixels
Height                           : 480 pixels
Display aspect ratio             : 4:3
Frame rate                       : 30.000 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.453
Stream size                      : 45.4 MiB (98%)
Writing library                  : XviD 1.2.1 (UTC 2008-12-04)

Audio
ID                               : 1
Format                           : MPEG Audio
Format version                   : Version 2.5
Format profile                   : Layer 3
Codec ID                         : 55
Codec ID/Hint                    : MP3
Duration                         : 1mn 31s
Bit rate mode                    : Variable
Bit rate                         : 55.5 Kbps
Nominal bit rate                 : 64.0 Kbps
Channel(s)                       : 1 channel
Sampling rate                    : 11.025 KHz
Stream size                      : 619 KiB (1%)
Alignment                        : Aligned on interleaves
Interleave, duration             : 52 ms (1.57 video frames)
Interleave, preload duration     : 518 ms
Writing library                  : LAME3.98r
Encoding settings                : -m m -V 4 -q 2 -lowpass 5.5 --abr 64
After Avidemux
Code:
General
Complete name                    : E:\Temp\MVI_3249_agk1r.avi
Format                           : AVI
Format/Info                      : Audio Video Interleave
File size                        : 45.5 MiB
Duration                         : 1mn 31s
Overall bit rate                 : 4 175 Kbps

Video
ID                               : 0
Format                           : MPEG-4 Visual
Format profile                   : Advanced Simple@L5
Format settings, BVOP            : Yes
Format settings, QPel            : No
Format settings, GMC             : No warppoints
Format settings, Matrix          : Custom
Codec ID                         : XVID
Codec ID/Hint                    : XviD
Duration                         : 1mn 31s
Bit rate                         : 4 175 Kbps
Width                            : 640 pixels
Height                           : 480 pixels
Display aspect ratio             : 4:3
Frame rate                       : 30.000 fps
Color space                      : YUV
Chroma subsampling               : 4:2:0
Bit depth                        : 8 bits
Scan type                        : Progressive
Bits/(Pixel*Frame)               : 0.453
Stream size                      : 45.4 MiB (100%)
Writing library                  : XviD 1.2.1 (UTC 2008-12-04)

Audio
ID                               : 1
Format                           : MPEG Audio
Codec ID                         : 55
Codec ID/Hint                    : MP3
Duration                         : 1mn 31s
Bit rate                         : 56.0 Kbps
Channel(s)                       : 1 channel
Sampling rate                    : 11.025 KHz
Stream size                      : 625 KiB (1%)
Alignment                        : Aligned on interleaves
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