ffmpeg video splitting help

[hss2293]

I have converted a video using ffmpeg and then
I am using the following command to split a video

ffmpeg -i video.3gp -ss 00:20:00 -t 00:05:00 -vcodec copy -acodec copy output.3gp

The problem is that the in video the audio comes first and lip movements are later means audio is coming before the words are spoken. While when i download the video without splitting there was no error.
Please tell me how to fix this issue.

[Budman1]

Make sure there isn't a delay to audio set in Media Infor Audio:
Audio
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 10
Duration : 6mn 17s
Bit rate : 188 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 44.1 KHz
Compression mode : Lossy
Delay relative to video : 31ms
Stream size : 8.44 MiB (28%)

This may cause it to play correctly but split wrong.

Also try the -ss string before the -I file and after. See the below split with :
ffmpeg -ss 00:00:04 -t 00:00:05 -i muzzleflash.flv vcodec copy -acodec copy muzzleflashbefore.flv
and
ffmpeg -i muzzleflash.flv -ss 00:00:04 -t 00:00:05 -vcodec copy -acodec copy muzzleflashafter.flv

Note the Frame and time in upper left of each sample



It makes a difference .