Contributing to Kdenlive

Tue Aug 28 19:10:56 BST 2018

Hey Eugen,

yeah I am already trying to combat the pops by adding fade ins and fade outs at the end of every clip, which helps sometimes.

But whenever there is a Slide transition, I can't here a pop during playback, but the timeline indicator will halt/stop for a millisecond during that transition period in the timeline, and that is exactly where the pop occurs in the rendered output.

And it seems that nothing I do, in terms of switching different audio codecs, containers, even moving the clips or the transition where the pop occurs, solves the problem. Once the pop is there, it will continue to come up as if it was programmed at that specific spot.

The only thing that seems to help is lowering the framerate by changing to a different project profile, but that completely messes the audio up, putting it out of synch etc.

I will try going back to Ubuntu 16.04, maybe it's something about Alsa/Pulseaudio on 18.04. Really at the end with my math here.

Thank you for your patience, I really appreciate it

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‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On August 28, 2018 7:06 PM, Eugen Mohr <eugen.mohr at gmx.net> wrote:

> Hi John
>
> As I don’t see your timeline my guess is that this pops/clicks coming from audio clipping. Meaning you reach 0dB or higher because you add one audio on each other.
>
> To avoid this make an audio crossfade. On 1 audio track a fade out and on the other a fade in.
>
> Audio crossfade seems still on the wish list. https://forum.kde.org/viewtopic.php?f=270&t=127698#p340370
>
> Eugen
>
> Am 28.08.2018 um 16:54 schrieb Steve Brodie:
>
>> Hi John,
>>
>> If it is only happening on transitions etc. could you do an export of your audio only at 25fps, bring it back into Kdenlive as one continuous WAV file and mute all the edited audio tracks and export again at 60fps? Or does that introduce sync issues?
>>
>> Steve
>>
>> On 28 Aug 2018, 13:00 +0100, johnar1 [<johnar1 at protonmail.com>](mailto:johnar1 at protonmail.com), wrote:
>>
>>> Hi, Eugen!
>>>
>>> Yes, during problem there are no pops. They only appear in the rendered output file. Another thing I have noticed is, that they only happen at the beginning or end of overlapping clips when there is a transition (Slide) or Volume Keyframable Effect involved.
>>>
>>> Yes sir, I use Lubuntu 18.04 and Kubuntu 18.04.
>>> I just checked and the clips are ususally 44.1khz 16bit.
>>>
>>> The only way I can get rid of all pops is if I render with a 25FPS profile.
>>> 50FPS, 59.9 and 60FPS all produce the same pops.
>>>
>>> It's driving me so insane omg, I can't sleep anymore.
>>>
>>> Sent with [ProtonMail](https://protonmail.com) Secure Email.
>>>
>>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>> On August 27, 2018 8:58 PM, Eugen Mohr [<eugen.mohr at gmx.net>](mailto:eugen.mohr at gmx.net) wrote:
>>>
>>>> Hi John
>>>>
>>>> I assume your audio file is not proper because FFMPEG can handle 44.1kHz. As Vincent Pinon mentioned: check if the audio is: 44.1kHz, 16 bit, WAV pcm (i.e. with the program MediaInfo). This is CD standard. Maybe 24bits work as well.
>>>>
>>>> Do you have this problem at playback or after you have rendered the video out?
>>>>
>>>> BTW: you are on Linux?
>>>>
>>>> Eugen
>>>>
>>>> Am 26.08.2018 um 22:28 schrieb johnar1:
>>>>
>>>>> Eugen, would you mind being a little more specific on what you meant by 44.1khz audio and 60FPS video interfering with each other over time, which causes clicks? I have searched everywhere on google but could not find anything.
>>>>>
>>>>> Is there a solution for this problem apart from converting every audio track to 48khz?
>>>>> Switching the 60FPS profile to 25FPS and rendering the audio produces no clicks, but the audio has multiple blank parts and is unusable.
>>>>>
>>>>> Hope you can give a little more insight in this matter.
>>>>>
>>>>> Thanks a bunch!
>>>>>
>>>>> Sent with [ProtonMail](https://protonmail.com) Secure Email.
>>>>>
>>>>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>>>> On August 21, 2018 8:53 PM, Eugen Mohr [<eugen.mohr at gmx.net>](mailto:eugen.mohr at gmx.net) wrote:
>>>>>
>>>>>> Hi John
>>>>>>
>>>>>> It comes 2 things to my mind:
>>>>>> -    Do you cut the audio at the zero point? In Audition (for example) is a function that you can cut only at that point (when the wave goes through zero) to avoid clicks.
>>>>>> -    When audio frequency (i.e. 44.1kHz) and video frequency (i.e. 60fps) interfere each other after a time and from there you get clicks. Video rendering is always video frequency driven. This would be a FFMPEG problem.
>>>>>>
>>>>>> Merlimau
>>>>>>
>>>>>> Am 21.08.2018 um 19:55 schrieb johnar1:
>>>>>>
>>>>>>> Hey Jean, thank you for that valuable info.
>>>>>>>
>>>>>>> I have tested the 18.08 version that you linked and unfortunately the pops at the beginning of audio clips still occur, but I have made an interesting discovery.
>>>>>>> When I render the entire project, there are three pops at the beginning of 3 clips, let's say at 01:23, 02:02 and 03:15 in the time line.
>>>>>>> These audio pops only come up in the rendered output, not during playback.
>>>>>>> When I only render a small selected zone surrounding the area where I know the pop will be, it does not occur.
>>>>>>> Only when I render the full project, they appear.
>>>>>>> I have tried this with all three known audio pops that I have spotted in the fully rendered project, and each time they disappear when I only render a selected area around them.
>>>>>>>
>>>>>>> The next thing I have noticed is that switching the playback settings betwen SDL and RTAudio  can affect this issue as well.
>>>>>>>
>>>>>>> As you know me now, I will now enter full testing mode and report back to you with a more detailed analysis.
>>>>>>> I will compile the latest melt, ffmpeg and co in order to provide a full report, but I will use the AppImage versio 18.8.0 which you have suggested.
>>>>>>>
>>>>>>> Anything else I should consider?
>>>>>>>
>>>>>>> Best regards,
>>>>>>>
>>>>>>> John
>>>>>>>
>>>>>>> Sent with [ProtonMail](https://protonmail.com) Secure Email.
>>>>>>>
>>>>>>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>>>>>> On August 20, 2018 10:23 AM, Jean-Baptiste Mardelle [<jb at kdenlive.org>](mailto:jb at kdenlive.org) wrote:
>>>>>>>
>>>>>>>> On 18.08.2018 14:55, johnar1 wrote:
>>>>>>>>
>>>>>>>>> Hey Jean and guys!
>>>>>>>>
>>>>>>>> Hello Johnar!
>>>>>>>>
>>>>>>>>> I have uncovered a new problem with the latest stable AppImage 18.04.1 release of kdenlive which is very troublesome.
>>>>>>>>>
>>>>>>>>> Randomly, kdenlive will cause a "click" or "pop" sound at the beginning of an audio track. I have observed that this happens the most when two audio tracks are overlapping or a cut has been made at the beginning of the a clip.
>>>>>>>>>
>>>>>>>>> I have also found that audio pops disappear in the same footage disappear when switching from SDL to RTAudio in the settings.
>>>>>>>>>
>>>>>>>>> I am using a fresh install of Kubuntu 18.04 with updates and
>>>>>>>>> Mlt and ffmpeg versions all from the Appimage, so this has to be a thing in kdenlive or maybe the latest Alsa / Pulseaudio package?
>>>>>>>>>
>>>>>>>>> I have tried some stuff suggested in forums such as exporting only the audio in wav, but without luck.
>>>>>>>>
>>>>>>>> I have just uploaded the 18.08.0 AppImage containing the latest MLT. Could you check if the problem still happens ?
>>>>>>>> It is available here:
>>>>>>>>
>>>>>>>> https://files.kde.org/kdenlive/release/kdenlive-18.08.0-x86_64.AppImage.mirrorlist
>>>>>>>>
>>>>>>>> Thanks for your feedback.
>>>>>>>>
>>>>>>>> Jean-Baptiste
>>>>>>>>
>>>>>>>>> Any ideas?
>>>>>>>>>
>>>>>>>>> Regards
>>>>>>>>>
>>>>>>>>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>>>>>>>>> On July 26, 2018 9:20 AM, Jean-Baptiste Mardelle [<jb at kdenlive.org>](mailto:jb at kdenlive.org) wrote:
>>>>>>>>>
>>>>>>>>>> On 23.07.2018 00:21, Juku Trump wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> Hello Juku!
>>>>>>>>>>
>>>>>>>>>> Thanks a lot for your contribution and sorry for my late reply. Your help is very welcome. I have now merged your contribution. Regarding the tests, they need some work and currently don't all pass and crash. We need to work on that.
>>>>>>>>>>
>>>>>>>>>> Regarding other tasks, we really need to make a list of UI improvements that could be done without too much knowledge of the whole code. I will try to spend some time on it tomorrow, help is welcome. But basically, if there is any UI related thing that you want to improve, feel free to ask and we can guide you if needed.
>>>>>>>>>>
>>>>>>>>>> Best regards,
>>>>>>>>>>
>>>>>>>>>> Jean-Baptiste
>>>>>>>>>>
>>>>>>>>>>> My name is Juku. I am a film hobbyist and I have been using Kdenlive for about 8 years. As I'm also a developer, I thought I would try my hand on contributing to Kdenlive.
>>>>>>>>>>>
>>>>>>>>>>> I have mostly been a web developer so far, so I do not have much experience with C++ (except for some tutorials) and I have never done any Qt development.
>>>>>>>>>>>
>>>>>>>>>>> I viewed the "Junior Jobs" section in Kdenlive Development Information page and tried to fix #384511 for start ("New project window does not fit to laptop screen (1366x768)"). Thanks to a hint by Christoph Feck in the comments below that bug, I got it fixed and submitted the patch ([D14281](https://phabricator.kde.org/D14281)) for review.
>>>>>>>>>>>
>>>>>>>>>>> Currently I'm having some trouble with the automated tests. Should they succeed in their current state or are there some known problems with them?
>>>>>>>>>>>
>>>>>>>>>>> It would be helpful if someone would suggest some other tasks which I could start with.
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Juku
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