video sync

Hello Jukingo

I am converting this to a bug report and referring it to Audio Syncing

I have started flagging all audio-sync bugs to make it easier to fix them.

Best wishes, Helen

Hello Helen,

I guess you are working on the OpenShot project with Jonathan?

I have read some of the posts that you forwarded to me and most of it mentioned the syncing problem when you export. However, in my case the syncing problem happens when just playing the .osp file as well without even going to export (but it DOES appear in an exported file as I tested this morning). I am using an .flv video file and I have ran that file in many different ways and I have noticed that sometimes the video hangs up and runs slower than the audio. Sometimes it 'jumps' and skips ahead, and then it is right on. Running the file by itself does minimize the problem, but then again that is not what OpenShot was made for, right? The point is to edit the video files. Cutting the files does affect the sync, but isn't as bad as increasing/decreasing the video file's length.

I have not tested too many other files outside of the .flv files I normally use as I am just beginning to use the program. So I am not sure if the problem is related to just those files.

I have to play around with it some more.

Thanx,

Geo

Hello jukingeo,

Yes I noted that your problem was different, which is why I logged it as
a separate bug report.

I have linked all the syncing problems together so that whoever is
working on them has an overall picture of the various syncing problems.

Yes I am one of the OpenShot Developers Team along with; Jonathan, Andy,
TJ, Olivier and Karlinux.

I have experienced exactly what you describe. In my case it was a
soundtrack I ripped from a video clip I had shot, and converted to mp3
to edit in Jokosher. I then laid down the soundtrack with the video clip
in the track above. If I got the sound in sync for one part of the
track, it was out of sync for other parts of the track. The clip was of
some performers on trapeze who were leaping to the ground at intervals
through the performance. Each drop to the ground being accompanied by a
bang. In some places the bang coincided with the impact. In other places
the bang was a second or so before the impact, and in other places the
bang was a second or so after the impact.

I suspect that the video and sound were being played at different rates.

Helen McCall

On Sat, 2009-09-12 at 19:45 +0000, jukingeo wrote:
> Question #82556 on OpenShot Video Editor changed:
> https://answers.launchpad.net/openshot/+question/82556
>
> Status: Answered => Open
>
> jukingeo is still having a problem:
> Hello Helen,
>
> I guess you are working on the OpenShot project with Jonathan?
>
> I have read some of the posts that you forwarded to me and most of it
> mentioned the syncing problem when you export. However, in my case the
> syncing problem happens when just playing the .osp file as well without
> even going to export (but it DOES appear in an exported file as I tested
> this morning). I am using an .flv video file and I have ran that file
> in many different ways and I have noticed that sometimes the video hangs
> up and runs slower than the audio. Sometimes it 'jumps' and skips
> ahead, and then it is right on. Running the file by itself does
> minimize the problem, but then again that is not what OpenShot was made
> for, right? The point is to edit the video files. Cutting the files
> does affect the sync, but isn't as bad as increasing/decreasing the
> video file's length.
>
> I have not tested too many other files outside of the .flv files I
> normally use as I am just beginning to use the program. So I am not
> sure if the problem is related to just those files.
>
> I have to play around with it some more.
>
> Thanx,
>
> Geo
>

Hello Helen

<Yes I noted that your problem was different, which is why I logged it as a separate bug report. I have linked all the syncing problems together so that whoever is working on them has an overall picture of the various syncing problems. Yes I am one of the OpenShot Developers Team along with; > Jonathan, Andy,> TJ, Olivier and Karlinux.>

I have noticed a few minor issues with OpenShot, but a couple I have found some work arounds for, but this one was a glaring problem. The other problem I had when I left off with Jonathan was that of poor resolution when trying to export, even when using the highest settings for video. I still have yet to get that problem resolved, but this one is a biggie.

<< I have experienced exactly what you describe. In my case it was a soundtrack I ripped from a video clip I had shot, and converted to mp3 to edit in Jokosher. I then laid down the soundtrack with the video clip in the track above. If I got the sound in sync for one part of the track, it was out of sync for other parts of the track.>>

The video seems to be 'hanging' up every so often. This even happens with an unaltered video track, but not as often. Usually a single track within the program of audio and video together will play fine, but start adding tracks or doing what I did and things get sticky. I have a funny feeling the more I add the worse it will get.

<<The clip was of some performers on trapeze who were leaping to the ground at intervals through the performance. Each drop to the ground being accompanied by a bang. In some places the bang coincided with the impact. In other places the bang was a second or so before the impact, and in other places the bang was a second or so after the impact. I suspect that the video and sound were being played at different rates. Helen McCall>>

When I was last talking to Jonathan I suggested to send a clip to him in relation to my pixelation problem I had with exporting. Likewise I probably would send my .osp file to you for my video edit, however, I think I will need a direct email for that because I don't think your site accepts attachments, right?

However, from your explanation, it sure does sound like the same issue. I am wondering if the audio and video are using different buffers and perhaps there is more space on the audio buffer than the video one. If there is a slight dip in system resources (of which we already established OpenShot IS a resource hog) then perhaps the video buffer is filling up faster. When full, it could create that hiccup. The video sometimes 'jumps' or skips ahead as well and in that manner it would make the audio sound like it is behind rather than ahead. But usually it seems like the video is lagging behind the audio.

Do you have an idea of what could be causing the issue? I am hoping it is an easy fix. I would like to use OpenShot to set up a presentation I am working on. I have Cinelerra, but it is a bit difficult to get around. OpenShot looks to be a more advanced version of Windows Movie Maker and it is very easy to learn. So I really would like to stick with it.

Anyway, if there is any information or files I am working on that you would like to see, let me know.

Thanx,

Geo

The "hanging up" is a bug 403154 which is being worked on

It appears to be a problem with ffmpeg handling the audio channel.

I am linking this "question" to that bug also ;-)

Best wishes, Helen

Hello Helen,

So you HAVE found a bug in the video/audio sync as well. That means you CAN see how the video sometimes 'hangs up'. The video sometimes can skip ahead too and thus it appears that the audio is going out of sync, but in reality it is the video that the culprit. The audio plays back fine, no stutterin no skipping. The video is going out of sync.

Are you close to a solution? I hope so. I have been talking about OpenShot in other forums and others have been trying it out and like the program. I said thus far it seems like the highest promise for a simple video editor WITH audio mixing for Gnome.

So I am crossing my fingers that the problem isn't a big one to fix.

Thanx,
Geo

Hello Helen,

How far are you in terms of the video sync bug fix? Will there be a new version released soon?

I have version 0.9.22 (that is still the current one right?).

Thanx,
Geo

This question was expired because it remained in the 'Open' state without activity for the last 15 days.