Contributing to Kdenlive

Tue Aug 28 20:13:08 BST 2018

Hi John

If you say “programmed”. What is coming to my mind is hardware. Do you 
have a sound card or video card involved which helps rendering? I don’t 
know if there are some temp files in Kdenlive who stores some 
intermediate steps?

MLT, QT, FFMPEG? I don’t know the software routing from pressing play 
until something happens.

Eugen

Am 28.08.2018 um 20:10 schrieb johnar1:
> 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
>
>
> Sent with ProtonMail <https://protonmail.com> Secure Email.
>
> ‐‐‐‐‐‐‐ 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>, 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> 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> 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> 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> 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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