Author Topic: Smart Rendering Panasonic GH4 UHD MP4 Files in a Batch  (Read 3344 times)


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Smart Rendering Panasonic GH4 UHD MP4 Files in a Batch
« on: September 21, 2015, 09:09:07 AM »
I have been searching for a way to smart render UHD (4k) MP4 files shot with my Panasonic GH4. I usually edit the files in Sony Vegas Pro and, since it cannot smart render such files itself, I would like to export an EDL or batch list that another program can use.

My fruitless search so far is documented at A user there has replied that Avidemux can do this. I have tested it using "MP4 muxer" output and it kind of works, but unfortunately Vegas Pro decodes the output files' as 29.971p, so they don't quantize properly if mixed with original GH4 files which decode at 29.970. Vegas also renders the output files with 3 duplicate frames at the start and 2 at the end. However I can write a Vegas script to truncate the duplicate frames on the timeline, and then the file quantizes and syncs properly despite the reported difference in frame rate. These problems do not appear to occur in Premiere Pro.

My questions are:

1. Is there a way to import an EDL list into Avidemux, or to convert an EDL into a batch?
2. What format EDL file is expected? (I can get a Vegas Pro script written to export the correct format)
3. Is there a way to automatically trim to i-frames, expanding to i-frames (full GOPs) outside the edit points rather than contracting? Or does that always happen anyway?
4. Is there a way to mux the source files' PCM audio? (it wouldn't do this in MP4 output so I had to compress audio to another format)
5. Is there a way to retain the camera metadata?
6. Any way to deal with the minor frame rate difference and the duplicate frames?

Jan Gruuthuse

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Re: Smart Rendering Panasonic GH4 UHD MP4 Files in a Batch
« Reply #1 on: September 23, 2015, 06:22:43 AM »
EDL (Edit decision list) =  under file there are 3 project files: QTscript Project, Tinypy Project and SpiderMonkey Project.
Do something small in avidemux: edit small sample video and cut a block in between, select start and end with up down keyboard keys (key frame), simultaneous key press [Ctrl] [X].
Save in each project and compare the saved project file if it resembles something to EDL

I I understand you correctly you want to use avidemux for post processing, editing done in Sony Vegas Pro. Not certain this is going to work.

Main advantage with avidemux you can edit without re-encoding, just leave Video Output and Audio Output set to Copy and select Output Format to MP4v2. Test again with a small video sample approx. 1' in duration.
See small real time demo 34.8 MB in size Avidemux Edit Cut Trim

4) if audio is stereo, you could drag and drop to video to audacity and process audio in audacity and then export to the required audioformat. Then replace existing audiotrack in avidemux by the newly saved audacity track with Menu: Audio: Select Track: change [selected track] to [.... Add Audio Track] and select newly save audio track.

5) most likely you can transfer metadata from original video to new video with ffmpeg: Where Are the Metadata Tags

Sorry I don't have answers to your other questions (I'm a basic user)
« Last Edit: September 23, 2015, 07:23:33 AM by Jan Gruuthuse »


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Re: Smart Rendering Panasonic GH4 UHD MP4 Files in a Batch
« Reply #2 on: October 03, 2015, 04:58:26 AM »
Thank you very much for your reply Jan. I ended up doing this with FFmpeg. My workflow, starting and finishing with Sony Vegas Pro, is described here, if anyone is interested.