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• How to speed up black video creation with FFMPEG ?

  2 décembre 2017, par Rick Sullivan

  I have been generating static black videos as backgrounds using FFMPEG’s color source. This works fine for smaller and shorter videos, but I need to be able to generate long 1080p black videos quickly.

  For example, I can generate a two hour long 1080p@30fps video using :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -t 7200 test.mp4

  But this will take over 45 minutes to run.

  There are options that speed up runtime, like using the ultrafast preset :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -preset ultrafast -t 7200 test.mp4

  Which will take around 20 minutes to run. Better, but not good enough for doing this en masse.

  Are there any other options to drastically speed up runtime ?

  Intuitively, I am generating a static video where only video duration varies, so it seems like there should be an approach that is restricted only by disk write speed. All of these options are very CPU intensive and seem to be doing more processing than is necessary for my use case.

• Encoding 4K 60Hz lossless from a capture card

  13 décembre 2017, par Alex Pizzi

  Windows 10 64-bit
  Ryzen 7
  GTX 1080
  32GB RAM

  Hi all,

  I’m trying to encode 4K 30/60Hz video in a lossless format from a 4K capture card and everything I’ve tried gives me a similar error as in the linked image, [real-time buffer too full or near too full frame dropped]

  [Not mine]
  https://cloud.githubusercontent.com/assets/4932401/22171307/ef5c9864-df58-11e6-8821-4b74ce3f32d0.png

  This is the command I’ve tried most recently :

  ffmpeg.exe -f dshow -video_size 3840x2160 -framerate 30 -pixel_format bgr24 -rtbufsize INT_MAX -i video="MZ0380 PCI, Analog 01 Capture" -vf fps=30 out%d.BMP

  With the images dumped to a 10G RAM disk or 850 EVO. I’m doing this to skip the encoding step.

  I get the same error when encoding with h265 lossless and NVENC h265 lossless.

  I need the video to be lossless as it will be used to test hardware h265 encoders.

  Video source is a 4K Blu-ray.

  Any help would be greatly appreciated. Thank you.

  -Alex P

• What is the best solution to convert old videos to newer more optimised formats ? [on hold]

  9 septembre 2019, par Jack

  Not too sure if this is the wrong place - please move it as I couldn’t find a more suitable network

  I have loads of media (Movies, TV Shows) as well as home videos (old VHS stuff ripped using some awful VHS to digital kit)

  Most of the movies/TV shows are in H264 (MP4/MKV containers) format, however some older ones are in AVI and WMV - I’d like to convert these into either H264 or a newer format (HEVC ?) To save some disk space and also because WMVs and AVIs are getting harder to deal with nowadays. I’m concerned about losing quality and am wondering what would be the best compromise in terms of converting these to HEVC/MPEG4’s encoder quality settings as compared to the data savings.

  The media collection of TV shows/movies, I don’t mind too much about losing some quality but the home videos/VHS tapes I have in old file formats, the storage factor for these is less important but I was wondering what I’d need to do to convert old AVI’s/MPEG2’s to MPEG4/HEVC - mainly if it is possible to convert one of these old video files to a newer format, without loss of quality, I thought the newer video encoding’s had lossless and lossy compression, but I could be completely wrong and don’t know much about video codecs.

  I was more curious on the best solution to do this as, Googling it gives me loads of commercial software and I’d rather have something which I can use command line/programmatically against my entire libraries. I also couldn’t find anything on these commercial sites about the technicals of re-encoding video so, was wondering if anyone had any experience with any command line applications/have an understanding of the video codecs.