Registered Member
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Dear forum,
After lots of hours of trial'n'error I would like to share with you the results of my search for a good workflow with kdenlive. May it be helpful to some of you. ## SHOOTING ## I'm shooting with a Panasonic SD300, which gives me AVCHD-Clips (container: MTS) in 1080i/50fps. Audio format is Dolby Digital (AC-3), Sourround 5.1 @ 384 kbps ## TRANSCODING ## I'm not a professional, nor do I have a HD-TV or any other HD monitor. Therefore I do not need 1920x1080 (but of course I keep the original files for future times) My pc is just a dual core (HP TX 2500 Tablet PC, nice machine btw) so I'm not able to cut AVHCD directly. And I don't have endless space on my hard disk. Putting all this together I decided to transcode the MTS-clips to DNxHD 720p/25fps at 60 Mbps container: mov audio: pcm_s16sle, 48kHz (For this task I'm using a script, which I'm describing in another post: http://kdenlive.org/forum/bash-script-transcoding-avchd-clips-dnxhd ) The DNxHD specifications states the 720p@60M as a valid combination of resolution and bitrate. (1080p/25fps@36M is even smaller, but editing 720p is a bit smoother on my machine) Of course: This is not a real lossless transcoding. But for my eyes and my needs the quality is more than enough. Actually I hardly find any differences between original and transcoded files (But this may be due to the missing HD monitor) I would love to transcode the audio to Vorbis, but unfortunately Vorbis is not allowed within a mov-container. ## TRANSCODING AUDIO ## I'm searching on jamendo.com for nice background music. The files you will get from there has a sample rate of 44100 kHz, not 48000 kHz as the audio-streams in my video clips. When adding this files to the timeline in kdenlive I encountered some strange effects: The audio-clips showed a different length, were cutted a the end or something like this. My resolution: Transcoding all clips to the WAV-format. For this task I'm using Audacity. You have to import the files and setting the project bitrate to 48000 kHz. You can import all your files at once, each one to a different track. Audacity is able to export the tracks seperately as single files. ## EDITING ## Since all my video clips are 1280x720 now, I'm using the kdenlive profile "HD 720p 25fps". ## ARCHIVING ## For archiving purposes I tried the lossless settings in kdenlive, but nothing really works for me: The ffv1 codec gives me a colorful ribbon at the bottom of the video-picture, the huffyuv codec (or the used avi-container?) crashes my video player totem. And even if they would work: The resulting files are far to big for me ... Showtime again for the dnxhd codec. I'm rendering the final project to DNxHD 720p/25fps at 60 Mbps container: mov audio: pcm_s16sle, 48kHz Which are exactly the same settings as above. It gives me a reasonable size (13 GB for half an hour) and -- as said -- a very good quality. ## SHARING ## For sharing the video with friends (mostly Windows users) I'm using H.264 in a MP4 container. The best tool for that is IMHO not kdenlive (sorry for saying that) but HandBrake from handbrake.fr I'm transcoding the DNxHD clip from the archiving step before with the "Normal" Preset in Handbrake, downscaling it to 768x432 pixel. 768x432 ... leads to a Pixel Aspect Ratio of 1:1 has a Display Aspect Ratio of 16:9 and 768 mod 16 = 0 , 432 mod 16 = 0 As far as I understand these are good foundations for downscaling a video. The resulting files are pretty small and have a good video quality. Most important: The files play well on my machine, bigger resolutions don't. ## AUTHORING A DVD ## Kdenlive has a good DVD wizard, but I found it helpful to tweak a bit the settings in the DVD profiles: Instead of b=5000k and maxrate=8000k I'm using b=8000k maxrate=9000k These are still valid settings acording to the DVD specifications, but gives a much better video quality. That's all folks. I'm looking forward to your comments. Where do you have a different workflow and why? Which tipps and tricks do you have for me? Thanks in advance. Jonathan |
Registered Member
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A good format (imho) for archiving purposes is mjpeg with a high quality setting, the loss is not noticable and yet the resulting file is far smaller than raw formats like y4m, huffyuv and ffv1. The drawback is that mjpeg only wants to sit in an avi container. Otherwise there is h264, which has, if you explore the command line version of x264, many tunable options, including I-frame-only encoding (like mjpeg does) and also a pure lossless setting (but with is not supported by every media application).
I don't understand why you want to achieve a pixel aspect ratio of exactly 1:1, as nearly all video codecs and containers provide signalling for the actual par, almost all video material uses a par unequal to 1:1, even DVD and 4:3 SD DVB. For DVD "quality" it's more or less custom to use DVD resolutions, like 720x576 by 25 fps or 720x480 by 30 fps (depening on your source material). The pixel aspect ratio is slightly off 1, but it doesn't matter, it gets corrected while playing. |
Registered Member
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Dear forum, (and thanks to eriksl for his comment)
since my first post things have changed a bit in kdenlive world and outside. I found a new, much more simple workflow which I would like to share with you. First of all, editing with proxy files has landed in kdenlive which is an impressive, outstanding feature. It allows editing of AVCHD footage even on my old hardware. I'm in the search for a good proxy profile: http://www.kdenlive.org/forum/finding-best-profile-proxy-encoding Right now I propose two profiles – high quality and low quality. high quality: -f matroska -vcodec mjpeg -qscale:v 3 -sn -vf scale=-1:432 -acodec pcm_s16le -ac 1 low quality: -f matroska -vcodec mjpeg -qscale:v 15 -sn -vf scale=-1:288 -acodec pcm_s16le -ac 1 As a side note: the syntax of ffmpeg/libav options has changed and kdenlive should consider to use the new one, i.e. "-c:v mjpeg -q:v 5 -c:a psm_s16le" ## EDITING ## I'm still shooting with a SD300 and since I'm not in the need of transcoding anymore, I'm using the following project profile HD 1080i 25 fps However, kdenlive kept complaining that my clips are 50 fps (which they are not, they are interlaced and have 50 fields (not frames) per second), so I had to deactivate the initial check for the correct profile in the settings. My low quality proxy profile from above suits my needs, so this my choice most of the times. ## EXPORTING ## I found that I need three different rendering profiles: --> One for sharing the files with friends (small filesize, compatible to windows) --> One for watching the movie for myself or with my family (decent filesize, good quality) --> And one visually lossless profile for archiving the movie with best possible quality Here we go: to share the movie: f=mp4 acodec=aac ac=2 vcodec=libx264 s=768x432 preset=veryslow tune=fastdecode crf=24 to watch the movie: f=matroska acodec=libvorbis ac=2 aq=3 vcodec=libx264 s=1280x720 preset=veryslow tune=fastdecode crf=21 to archive the movie: f=matroska acodec=libvorbis ac=6 aq=3 vcodec=libx264 s=1920x1080 preset=veryslow tune=film crf=18 You may find infos to these settings on http://mewiki.project357.com/wiki/X264_Settings Genereally I believe that we should trust in the default settings of encoders as much as we can. Rather than tweaking every single setting I prefer using the H.264 presets and the constant ratefactor crf to choose the right quality for my needs. That's all. Thanks for listening Jonathan |
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