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• How to encode bmp images to H264, H265 losslessly with and without Nvenc

  26 août 2020, par Hamza Ghizaoui

  So, let s assume that i have 5000 BMP images (1920x1080) that i want to encode into a video.

  


  I managed to do that losslessly using FFMPEG using the following 4 encoders :

  


  

  • libx264

  


  • libx265

  


  • h264_nvenc

  


  • hevc_nvenc

  


  


  The problem is that when i try to test my results using PSNR, i get extremly high values, in the 30-70 range. What is happening ?
Is the problem with color space conversion ? (None of the encoders above seem to support RGB, a conversion to YUV occur and I m assuming that a lot of averaging is happening. stuff that PSNR test is very sensetive toward).

  


  If my reasoning is correct, is it possible to encode BMP 100% losslessly. the resuling video will be streamed locally. the network is 10 GBS, so the size isn t that important.

  


  thank you

  


• FFMPEG - the video is out of sync with the audio

  5 août 2020, par mitsuki

  I tried to covert ISO file to m3u8, but the video is out of sync with the audio.

  


  I guess this is one of the reason.
First VOB file has only audio.
From second VOB file, there are audio and video.
When I play the m3u8, audio from first VOB and video from second VOB will start.
That's why probably the video is out of sync with audio.

  


  How do I skip First VOB file which has only audio.

  


  By the way, I am using this script.
I am looking forward to your advice.

  


  docker run —rm -it
  
-v $(pwd)/input :/config
  
jrottenberg/ffmpeg
  
-hide_banner
  
-y -i /config/input545.iso
  
-vf scale=w=640:h=360:force_original_aspect_ratio=decrease
  
-c:a aac
  
-ar 48000
  
-c:v h264
  
-profile:v main
  
-crf 20
  
-sc_threshold 0
  
-g 48 -keyint_min 48
  
-hls_time 6
  
-hls_playlist_type vod
  
-b:v 800k
  
-maxrate 856k
  
-bufsize 1200k
  
-b:a 96k
  
-max_muxing_queue_size 5000
  
-analyzeduration 60M
  
-probesize 60M
  
-max_interleave_delta 0
  
-hls_segment_filename /config/360p_%03d.ts /config/360p.m3u8

  


  Thank you.

  


• Linux - ffmpeg 3.4.6 vs. 4.2.1 - bash script with Tee (record & stream) runs in older version just fine - what needs to change for new version ?

  22 juillet 2020, par pomptondrive

  Thanks for reading my post. I have a bash script that I tested and it ran just fine ; although I was putting the script into identical hardware as the test computer, I forgot that the target computer would have a newer version of ffmpeg. It should be simple. I'm splitting the signal, recording, and streaming via UDP. Here's the script, that runs just fine with ffmpeg 3.4.6 :

  


  ffmpeg -f v4l2 -i /dev/video0 -t 00:30:00 -vf "drawtext=fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf:text='%{localtime\:%T}':x=20:y=20:fontcolor=white" \
-profile:v high -pix_fmt yuvj420p -level:v 4.1 -preset ultrafast -tune \
zerolatency -vcodec libx264 -r 15 -b:v 512k -s 960x720 -f mpegts -flush_packets 0 \
-f tee -map 0:v "/media/dkm/video_usb/videos/video_$(date +%Y-%m-%d_%H.%M.%S).mkv|[f=mpegts]udp://192.168.0.19:5000?pkt_size=1316"


  


  I could try to downgrade, but that doesn't seem right, since that computer is running Linux Mint 19.2 and the original test computer was Ubuntu 18.4 LTS. Is there something basic that I need to change for v. 4.2.1 ?

  


  I'm hoping that this is a quick fix, since it runs in the old version, but I've learned not to get my hopes up for such things. Any help would be appreciated. I've perused the documentation, but I wasn't able to see anything salient. Thanks in advance !