Re: [Kdenlive-devel] Audio sync issue

[Dan D. <da...@de...>]

On Sun, Feb 10, 2013 at 7:41 PM, el jefe delito <elj...@gm...>wrote:

> > Can you reproduce the problem by simply placing a clip on a timeline
> > by itself, rendering that, make a new project, add the rendered clip
> > to a timeline by itself, and render that?
> > You should use lossless for an intermediate file
>
> Using Debian Sid on the single file named 'DSC_0124.MOV':
>
>    - *If i export DSC_0124.MOV to a Lossless H.264 Slow (the audio is in
>    sync after), and then export again to every format that I tried (H264,
>    MERG-4, MPEG2), I had sync issues after that second render.*
>    - If I export DSC_0124.MOV to mpeg2 the audio was correct the first
>    time, but exporting again to anything had audio sync issues after the
>    second render
>    - If I export DSC_0124.MOV to an h.264 and reexport to h.264, for
>    completeness, it still has sync issues after the second render.
>
> > If so, can you reproduce it using one of the binary builds I provided
>  > to this thread yesterday?
>
> Using DD's Ubuntu x64 build (on Debian) I have:
>
>    - If I export DSC_0124.MOV to lossless H.264 Slow and then export
>    again to anything, it had audio sync issues issues.
>    - If I export DSC_0124.MOV to FFV1 and export again to anything, *I
>    don't have sync issues*
>    - If I export my complex project (which started this conversation) to
>    FFV1 Lossless, and then to Youtube or MPeg4 or H264, *no issues*; the
>    audio syncs and things look and sound good
>    - If I export my complex project (which started this conversation) to
>    FFV1 Lossless, and then to Android, the render crashes
>
> Dan, I think that your builds have fixed or improved the syncing.  Is this
> coincidence that I'm asking about these issues now?
>

Not sure what you mean by coincidence; I explained the recent history.
Debian unstable is a few versions behind and only has a few patches to
address crashes and memory leaks.

That Android render profile uses a bunch of special x264 options, which may
no longer apply now because ffmpeg and x264 have changed so much. I wonder
if that is causing some grief or not. A quick test worked for me, and I
will need to try to better replicate your steps to look deeper. Anyways,
these mobile profiles were created in the infant days of smartphones and
are obsolete now. Many modern smartphones can decode 1080p H.264 now. Same
goes for the web video-sharing profiles; the old constraints are no longer
relevant.


> It seems, the answers lie in
> the newer release;
> the matching of profiles, clips, export framerates;
>

The matching of these things technically should not matter, but I would not
be surprised if that helps. I was just wondering if you actually noticed
this is required for your project or if you are echoing what was said here.


> and the use of Lossless as an intermediary format
>
>
> > Understandable, but for future reference you can also add the first
> > project to the second project as a clip.
>
> I've read this but I don't understand how.  If I try to "Add Clip", I get
> video formats to pick from but none of the projectname.kdenlive files
> appear.  I don't see an option to "Add Project" or "Embed Project".  How
> can I add a project?
>
>
Do you not have All Files as a Filter option at the bottom of the file
dialog? If not you can just clear the filter field to show all files.


> Thanks everyone!
>
>
> On Fri, Feb 8, 2013 at 3:06 PM, el jefe delito <elj...@gm...>wrote:
>
>> Thanks for getting back to me.
>>
>> > Are you referring to just image quality or also A/V sync?
>> Both the visual and the syncing look good.
>>
>> > Does the A/V sync look good in Kdenlive's monitors even after scrubbing
>> or seeking?
>> Yes, at all points during my editing process the sync seems to be just
>> fine.
>>
>> > Can you reproduce the problem by simply placing a clip on a timeline
>> > by itself, rendering that, make a new project, add the rendered clip
>> > to a timeline by itself, and render that?
>> I will try this tonight and get back to you.
>>
>> > If so, can you reproduce it using one of the binary builds I provided
>> > to this thread yesterday?
>> I will try this as well.
>>
>>
>> Thanks again!
>>
>>
>>
>>
>> On Fri, Feb 8, 2013 at 2:59 PM, Dan Dennedy <da...@de...> wrote:
>>
>>> On Fri, Feb 8, 2013 at 6:05 AM, el jefe delito <elj...@gm...>
>>> wrote:
>>> > Thanks for the help.
>>> >
>>> >
>>> >> To the original poster, you need to provide a sample file, the project
>>> >> settings, and the render settings in order to investigate.
>>> >
>>> > My Nikon clips are 1280x720 at 23.98 FPS so that's what I changed my
>>> project
>>> > file to use.  I exported this at the H.264 setting with default
>>> values, and
>>> > the output appears perfect.  However, I need a logo overlay /
>>> watermark and
>>> > trying to do that in the original project, the KDEnlive editor wanted
>>> to
>>> > composite that image with a specific video track; my video is edited
>>> and on
>>> > multiple tracks so I thought it'd be easier to add as a new project
>>> (and
>>> > yes, I'd lose some quality with the re-render).
>>>
>>> Understandable, but for future reference you can also add the first
>>> project to the second project as a clip. However, this H.264 profile
>>> is a very poor choice for this because it is designed for distribution
>>> not for editing because the GOP size (keyframe interval)) is set to
>>> 250 frames. At 23.98 fps, that makes the GOP over 10 seconds! That
>>> will make seeking and thereby a/v sync more challenging. You should
>>> use lossless for an intermediate file, and they are faster to encode
>>> as well.
>>>
>>> > Ok, so the first output looks great.
>>>
>>> Are you referring to just image quality or also A/V sync? Does the A/V
>>> sync look good in Kdenlive's monitors even after scrubbing or seeking?
>>>
>>> >  The next run, new project, same
>>> > project settings and using only the recently exported file and a
>>> > transparent-background jpg, however, tells me at Render time that
>>> there are
>>> > No Matching Profiles for the H.264 option — which should be the exact
>>> > profile that I just used!  How can it not match itself?  If I use it
>>>
>>> There appears to be a cosmetic bug here. In a fresh project, the first
>>> time you open the Render dialog it defaults to the HDV group, and
>>> indeed HDV is not compatible with 720p23.98 (according to MLT and
>>> Kdenlive). This message should not apply to the H.264 render profile
>>> as it has no restrictions like that, but I saw the warning as well
>>> when I used your overlay project. So, there is some state bug that
>>> makes the render dialog erroneously issue that warning.
>>>
>>> > anyways, I get audio sync issues worse than ever.
>>> >
>>> > Attached are the two projects I've been working on (normal edit, and
>>> then
>>> > where I just add the overlay watermark).  However, I don't have a
>>> short,
>>> > decent clip to use to demo these sync issues so I'll have to shoot that
>>> > later and send it in 10 hours or so.
>>> >
>>>
>>> Based on this info, I do not need the original camera clip because it
>>> is the render output of the first project that is giving you a
>>> problem. I have not yet been able to reproduce this. I am not trying
>>> to use your complex first project because that would take some time to
>>> recreate with my own assets, and it does not appear to be necessary.
>>>
>>> So, I locate a 1280x720@23.98 clip in my library, add it a kdenlive
>>> project with same settings, place it on a track by itself, and render
>>> it with the H.264 profile. I check the output in a couple of players
>>> including Shotcut (MLT-based) and Quicktime Player on OS X, both of
>>> which are playing it with good sync.
>>>
>>> I open your overlay kdenlive project and replace the clip that is on a
>>> track with the output from the preceding step. I render that out using
>>> the render settings stored in the project file you provided (dual pass
>>> H.264). The A/V sync of that output is good as well checked using same
>>> players.
>>>
>>> Can you reproduce the problem by simply placing a clip on a timeline
>>> by itself, rendering that, make a new project, add the rendered clip
>>> to a timeline by itself, and render that?
>>> If so, can you reproduce it using one of the binary builds I provided
>>> to this thread yesterday?
>>>
>>> ----------------------
>>>
>>