Editing 4k HEVC footage (Samsung NX1)

[racer-x]

Well Samsung is selling the NX1. It records HEVC 4096 x 2160 @ 24p and 3840 x 2160 @ 30p. I'm sure people that buy it will be scratching their heads trying to edit it. The only way I've found (so far) to edit HEVC natively is to use an editor that supports ffmpeg to import. I'm not sure this is ideal, but it can work. Here's what I've tried so far:

Aviutl - You'll need to change max resolution in System Properties to 4096 x 2160
ShotCut - It can import HEVC. This program has limited editing abilities and runs better under Linux than Windows.
Virtualdub - You can import HEVC via the latest ffmpeg input plugin or an Avisynth script.

I have a feeling Samsung will have a hard time selling these because of the difficulties. I'll wait till the price falls substantially and maybe I'll take the plunge.

Here is a site where you can download original source clips to try out for yourself: http://www.imaging-resource.com/news/2014/11/19/samsung-nx1-4k-video-samples-and-new-f...ailable-for-do

If you don't want to download large files like that, I trimmed (losslessly) two of them at 10 sec each using ffmpeg + stream copy. You can try and see for yourself. Maybe this thread might help someone searching for a way to edit HEVC without transcoding into an intermediate codec first.

[TreeTops]

Good work racer. Methinks that the general public will not be editing 4K directly for awhile.

[racer-x]

Option # 2: Transcoding to intermediate codec to facilitate editing.....................

This is easy to do in batch mode with ffmpeg. Copy and paste the scripts below into Notepad, edit path to ffmpeg (use 64-bit version!) and save as WhateverName.bat. Create a sub-folder called "INT" in your video clips folder. Then drag the 1st mp4 into the appropriate .bat file and all will be processed and save in the INT folder.

1) HEVC_AVC.bat - This is a good option, the quality/size is decent and is easier to work with than hevc...

SET PATH="E:\FFMpeg\64-bit"
for %%a in ("*.mp4") do ffmpeg -i "%%a" -c:v libx264 -level 50 -pix_fmt yuv420p -preset medium -crf 19 -g 24 -c:a copy -f mp4 "INT\%%~na.mp4"

pause

2) HEVC_ProRes.bat - This is also a good option for quality, but file size is much, much larger....

SET PATH="E:\FFMpeg\64-bit"
for %%a in ("*.mp4") do ffmpeg -i "%%a" -c:v prores -profile:v 1 -threads 8 -c:a pcm_s16le -ar 48000 -f mov "INT\%%~na.mov"

pause

3) HEVC_MPG.bat - This would be a good option, but Mpeg-2 is limited to UHD resolutions. It doesn't support a resolution higher than 4095. You can still encode with it if you use the "-strict -1" command. However Vegas won't recognize Mpeg-2 resolution higher than UHD. The switch is included in this script just the same...

SET PATH="E:\FFMpeg\64-bit"
for %%a in ("*.mp4") do ffmpeg -i "%%a" -strict -1 -c:v mpeg2video -pix_fmt yuv420p -q:v 4 -qmin 1 -g 12 -c:a mp2 -ar 48000 -ab 384k -f mpegts "INT\%%~na.ts"

pause

...And last, but not least, if you want to trim losslessly, you can use this script. Edit the "-t" command, path to ffmpeg and create a sub-folder called "CUT"

SET PATH="E:\FFMpeg\64-bit"
for %%a in ("*.mp4") do ffmpeg -i "%%a" -t 10 -c copy -f mp4 "cut\%%~na.mp4"

pause

[Selur]

Mpeg-2 is limited to UHD resolutions.

Is this a libav limitation? (if it is reporting it to the bug tracker and getting it fixed shouldn't be much of a problem)
Don't recall anything in the specification which limits the resolution to UHD and below. (sure some decoders will be limited, but afaik the standard itself
isn't limited that way)

However Vegas won't recognize Mpeg-2 resolution higher than UHD.

Complain to Sony.

... if you want to trim losslessly, you can use this script.

you have to do the same thing you do with all MPEG based formats you cut on key-frames.

-------------------------

The main problem I see atm. is that libav doesn't support conversions from and to Rec. 2020 (https://trac.ffmpeg.org/ticket/2382) atm. (and none of the ways you mentioned does )
The Sony NX1 does use Rec. 2020, doesn't it ?

[racer-x]

The main problem I see atm. is that libav doesn't support conversions from and to Rec. 2020 (https://trac.ffmpeg.org/ticket/2382) atm. (and none of the ways you mentioned does )
The Sony NX1 does use Rec. 2020, doesn't it ?

Good question. If Media Info is to be believed, then the answer is NO.

General
Complete name : E:\Stock\Stock_Footage_4K\NX1 4k_clips\HEVC\NX1_4k_24p.MP4
Format : MPEG-4
Format profile : Base Media / Version 2
Codec ID : mp42
File size : 165 MiB
Duration : 38s 384ms
Overall bit rate mode : Variable
Overall bit rate : 36.1 Mbps
Encoded date : UTC 2014-11-14 04:57:42
Tagged date : UTC 2014-11-14 04:57:42

Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main@L5.1
Codec ID : hvc1
Codec ID/Info : High Efficiency Video Coding
Duration : 38s 375ms
Bit rate : 36.0 Mbps
Width : 4 096 pixels
Height : 2 160 pixels
Display aspect ratio : 1.896
Frame rate mode : Constant
Frame rate : 24.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.169
Stream size : 164 MiB (99%)
Language : English
Encoded date : UTC 2014-11-14 04:57:42
Tagged date : UTC 2014-11-14 04:57:42
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 38s 384ms
Source duration : 38s 379ms
Bit rate mode : Variable
Bit rate : 192 Kbps
Channel(s) : 2 channels
Channel positions : Front: L R
Sampling rate : 48.0 KHz
Compression mode : Lossy
Stream size : 890 KiB (1%)
Source stream size : 890 KiB (1%)
Language : English
Encoded date : UTC 2014-11-14 04:57:42
Tagged date : UTC 2014-11-14 04:57:42
mdhd_Duration : 38384

......And for the record, ffmpeg always defaults to nearest key-frame / I-frame when you choose "-c copy"

[Selur]

Ah, okay it's 8bit content. Rec. 2020 is for 10&12bit content.

[racer-x]

Interestingly enough, if you do a google search for "editing hevc", this post comes up at #4. Hopefully someone will get some use from it................

It would be great if someone would contribute with other methods to help those who surely will come here for help.

[racer-x]

Well I just upgraded my PC to an i7 4790 with 12 GB RAM and wanted to see how well it could edit this 4k HEVC footage from Samsung NX1. It did very well actually. I did a screen recording while I edited a native 4k hevc clip. I just did quick basic edits and left the SysMonitor running for reference. It edited pretty smoothly using Aviutl and is very doable with a very fast PC.

Attached is the screenshot video and the export video.