| View previous topic :: View next topic |
| Author |
Message |
Joseph_sys
Advocate
Joined: 08 Jun 2004
Posts: 2712
Location: Edmonton, AB
|
 Posted: Wed May 14, 2008 11:29 pm Post subject: [SOLVED] video and audio out of sync |
 |
|
After multiplexing audio and video: | Code: | | mplex -f 8 -o final.mpg movie.m2v movie.ac3 |
the audio is out of sync with video.
Searching through the forums I've run onto this post
https://forums.gentoo.org/viewtopic-t-221411-highlight-mpeg2desc.html (last entry)
that suggest that: | Quote: | offsets can be obtained by using mpeg2desc (comes with dvdauthor): | Code: | | $ mpeg2desc < stream.vob | grep pts | head |
The audio offset is the difference between the first video pts, and audio pts. Pass this to mplex with -O and it works |
Running this code I get: | Code: | mpeg2desc < final.mpg | grep pts | head
0000080e: pes video 0; length=2028; hdr=16; pts 0.178 sec; dts 0.144 sec; (pext); pstd=237568 (scale=1024)
0000200e: pes private1, audio 0; length=2028; hdr=11; pts 0.178 sec; (pext); pstd=16384 (scale=1024)
0000280e: pes private1, audio 0; length=2028; hdr=8; pts 0.274 sec
0000380e: pes private1, audio 0; length=2028; hdr=8; pts 0.338 sec
0000400e: pes private1, audio 0; length=2028; hdr=8; pts 0.402 sec
0000480e: pes private1, audio 0; length=2028; hdr=8; pts 0.466 sec
0000580e: pes private1, audio 0; length=2028; hdr=8; pts 0.562 sec
0000600e: pes private1, audio 0; length=2028; hdr=8; pts 0.626 sec
0000680e: pes private1, audio 0; length=2028; hdr=8; pts 0.690 sec
0000800e: pes video 0; length=2028; hdr=13; pts 0.778 sec; dts 0.745 sec |
I'm not exactly sure which parameters to read. The first line "video 0; ... pts 0.178 sec"
second line "audio 0; ... pts 0.178 sec"
The "pts" are the same value; or am I reading the wrong line?
Last edited by Joseph_sys on Thu May 15, 2008 6:40 pm; edited 1 time in total |
|
| Back to top |
|
 |
yabbadabbadont
Advocate
Joined: 14 Mar 2003
Posts: 4791
Location: 2 exits past crazy
|
| Posted: Thu May 15, 2008 12:18 am Post subject: |
|
|
When playing the file with mplayer, you can adjust the audio delay using the + and - keys. Each key-press will adjust the delay by +/- 0.1 seconds.
I've used this in the past to determine the correct adjustment to use when re-mplexing the files. |
|
| Back to top |
|
|
Joseph_sys
Advocate
Joined: 08 Jun 2004
Posts: 2712
Location: Edmonton, AB
|
| Posted: Thu May 15, 2008 12:48 am Post subject: |
|
|
I'm not sure if I need to go down or up :-/
There is another switch "-m" so it should be: | Code: | | mpeg2desc -m < final.mpg |
it should give me a number but I'm getting: | Code: | mpeg2desc -m < final.mpg
Could not read |
|
|
| Back to top |
|
|
yabbadabbadont
Advocate
Joined: 14 Mar 2003
Posts: 4791
Location: 2 exits past crazy
|
| Posted: Thu May 15, 2008 1:10 am Post subject: |
|
|
| You just have to play with the + and - keys in mplayer until you get it to match up. If I remember correctly, it shows the current offset on screen each time you hit one of the keys. |
|
| Back to top |
|
|
Joseph_sys
Advocate
Joined: 08 Jun 2004
Posts: 2712
Location: Edmonton, AB
|
| Posted: Thu May 15, 2008 6:40 pm Post subject: |
|
|
| yabbadabbadont wrote: | | You just have to play with the + and - keys in mplayer until you get it to match up. If I remember correctly, it shows the current offset on screen each time you hit one of the keys. |
I think I solve it by adding "-M1" switch to transcode line.
| Quote: | Sync modes
-M mode [1]
demuxer PES AV sync mode (0=off|1=PTS only|2=full) |
It multiplexed correctly. |
|
| Back to top |
|
|
|
Multimedia
