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4

Minimal command line, for a GOP size of 2 seconds: ffmpeg -i input -force_key_frames expr:gte(t,n_forced*2) -c:v libx265 -x265-params open-gop=0:scenecut=0:repeat-headers=1 output.hevc Verification: ffmpeg -i output.hevc -c copy -bsf:v trace_headers -f null - After each line containing key frame e.g., Packet: 18115 bytes, key frame, no pts, dts 2319977, ...


4

Both files that don't play feature Opus as the audio codec. As per this site, Opus is not one of the supported audio codecs. Transcode the audio: ffmpeg -i in.mkv -c:v copy out.mkv


3

This command preserved the colorspace and also video didnt get darker after transcoding ffmpeg -i input.mp4 -color_primaries smpte170m -color_trc smpte170m -colorspace smpte170m -r 25 -crf 18 output.mp4 source: https://kdenlive.org/en/project/color-hell-ffmpeg-transcoding-and-preserving-bt-601/ more about colorspace: https://trac.ffmpeg.org/wiki/colorspace


3

For files already encoded to AVI, you'll have to extract the video to a raw HEVC stream first: ffmpeg -i in.avi -c copy -map 0:v -f hevc in.265 and then ffmpeg -framerate 30 -i in.265 -i in.avi -c copy -map 0:v -map 1:a -video_track_timescale 1k fixed.mp4 Replace the framerate value with the true rate of the video. Encode new files to MP4 or MKV. ...


2

Try Encoding using "--tune fastdecode" and also check if "Average Bitrate" with "2 Pass" is better than "Constant Quality" with your particular Decoder; trying to maintain Quality over Bitrate can spike the Bitrate (holding a particular Bitrate will drop the Quality on complex Scenes). Try a few Test Files (short Clips from your Source) and determine which ...


2

Summary response for summary question :) CRF 20 will look really nice 8-bit (no advantages over 10-bit) No tuning. Grain tuning is for grainy source (old content). SSIM is for testing. No additional parameters needed. VFR (same as source) I could really, really, reallly go down the rabbit hole with a more detailed answer, but I'll leave it at this for now.


2

The name for this feature is Multiview Video Coding (MVC): an stereoscopic video coding standard for video compression that allows for the efficient encoding of video sequences captured simultaneously from multiple camera angles in a single video stream Can't be done, at present. Not using open source tools. There may be academic or commercial ...


2

Can't comment on the soundness of your theory, but here's a way to do it. Not directly, but in a roundabout way. FFmpeg's segment muxer can break up a file at GOP boundaries, so running the command below generates a set of videos which each start with a keyframe but contain no other keyframes. ffmpeg -i test.mp4 -c copy -f segment -segment_time 0.001 -...


1

You've specified the encoding bit rate to be 5000*1000 kbs. So the constraint here is the file size, not the quality of the video (i.e., all of your videos will be approximately 5 kbs * duration in size, regardless of the choice of encoding). HEVC has the potential to have higher quality at a given bit rate, though it comes at a cost of encoding speed (i.e., ...


1

I've transcoded some of my AVC (h.264) 1080p movies to HEVC (h.265) with 2 pass encoding (using my GPU) and target bitrate set to 50% of original. The other streams (like audio and subtitles) were only copied into the new file. Mostly I'm using Potplayer to play these files with Madshi renderer, and I can't see any difference on a 55" 4k HDR TV with ...


1

Personally I always stick to multiple of 8 but here it is: Multiple of 4: In H.265, DCT can be done in 4x4 Transform Units, so it's not a problem for that. It can also use motion vectors for 8x4 or 4x8 Prediction Units if there is only a single reference frame, or 8x8 if there are 2 reference frames. I suspect this causes some inefficiency, but nowhere near ...


1

As the excerpt below says, A thread pool dedicated to a given NUMA node is enabled only when the number of threads to be created on that NUMA node is explicitly mentioned in that corresponding position "+,-,+" --> no numerals stated, hence a single pool. "8,+,+,+" --> numeral for node 0, hence that's one pool. The other nodes have no numerals, ...


1

With Mulvya's help, I figured out the issue. FFMPEG was using a codec tag of hev1, while Media Encoder was using hvc1. Nothing I tried in FFMPEG would change this. Mulvya suggested I use mp4box to repackage. mp4box -add out.mp4 -new final.mp4 didn't work. But, after a little more searching, I ended up following the suggestion here and used mp4box to ...


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