Bug 459684

Created attachment 152427 [details]
kdenlive import transcode options

SUMMARY
***
I love kdenlive, and I am so grateful to the developers giving their time, but I find the transcode options hard to understand. (This is when I click Project and select Add Clip or Folder).

STEPS TO REPRODUCE
1. Take a video on a mobile phone that saves it with variable frame rate. Copy the clip to the computer.
2. Start kdenlive, click Project and select Add Clip or Folder. The Transcode dialog pops up, because we can't edit clips with variable frame rate.
3. Open the drop-down list of transcode Options.

OBSERVED RESULT
The first 3 options are easy to understand, but the last 4 I found confusing:
1. Lossy x264 I frame only
2. Lossy x264 I frame only (NVidia GPU Video only)
3. Lossy x264 I frame only (NVidia GPU)
4. Lossy x264 I frame only (Video only)
I looked in the documentation for help, but couldn't find any. I hope someone can find time to provide help there.
The "I frame only" looked like a vertical bar separating the option into two parts. I didn't want to get only frames -- I wanted to get the audio as well. I asked for help in the Forum (https://forum.kde.org/viewtopic.php?f=265&t=176125&p=458018#p458018), and @bartoloni pointed me to a description of "i-frame" compression. I can now see that this refers to "i-frames only", not B-frames or P-frames. 

Here are some ways I could misunderstand these options:
1. Lossy x264 I frame only                     # ie. video frames only, no audio
2. Lossy x264 I frame only (NVidia GPU Video only) # Only videos made on a machine with an NVideo GPU or for processing only on a machine with an NVidia GPU 
3. Lossy x264 I frame only (NVidia GPU) # Only videos made on a machine with an NVideo GPU or for processing only on a machine with an NVidia GPU
4. Lossy x264 I frame only (Video only)

Since all 4 options only support "i-frame" compression, could we leave that bit out, and have a note in the dialog that kdenlive wants to make the new x264 video with "i-frame" compression, not "B-frame" nor "P-frame". Then there would be less to read in each option.

If the NVidia GPU refers to the machine on which the editing will be done, could there be a checkbox for that instead of two options containing "NVidia GPU"? (It is easier to put an explanatory comment beside a checkbox than in an option in a drop-down list.) 

Similarly, if the GPU option refers to the machine on which the video we are importing was made, again I think a checkbox would be better. (But how would the user know what machine the clip was made on?)

Finally, if "Video only" means that the transcode should drop the audio, I think it would be easier to understand if there were a checkbox labelled "Remove audio from output".

DESIRED RESULT
Taking a few guesses at what these options actually mean, I would find something like this easier to understand:
=============
The following clips are not usable for editing. This will transcode them in an edit-friendly format and replace the original ones in your project.
Note: the "x264" options will produce compressed files for us to edit, with some loss of video quality, using "i-frame" compression. (B-frame and P-frame are not available. For more information, see
https://en.wikipedia.org/wiki/Video_compression_picture_types)
<paths to input clips as at present>

[ ] The transcoded video will be processed on a machine with an NVidia GPU (if that's what the option means :-)
[ ] Output video only, not audio

AAC (output audio only)
Intermediate DNxHR HQ (Large files)
Lossless (Huge files)
Lossy x264 compressed video (Small files)
=============

SOFTWARE/OS VERSIONS
Windows: 
macOS: Big Sur (11.7)
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5

ADDITIONAL INFORMATION