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• FFmpeg command issue with johnvansickle.com/ffmpeg version

  21 mai 2018, par Bhumi Shah

  Command is working fine with latest version of ffmpeg but when I tried with johnvansickle ffmpeg, not working

  ffmpeg version: N-46084-gcae004cab-static
  

  command is:

  ffmpeg -i abc.mkv -vcodec copy -acodec copy abc.mp4
  

  Ffmpeg command error:

  [mp4 @ 0x5196680] track 1: codec frame size is not set
  [mp4 @ 0x5196680] opus in MP4 support is experimental, add '-strict -2' if you want to use it.
  Could not write header for output file #0 (incorrect codec parameters ?): Experimental feature
  

• Why does hard-coding subtitles into MKV cause resulting video length to be wildly incorrect ?

  21 mai 2018, par BudJB

  I am trying to encode an existing MKV with a video, audio, and several subtitle streams, such that video encodes with H264, audio encodes with AAC, and the second subtitle track is hard-coded into the video stream. I am using the myffmpeg GUI frontend, but can view and modify the ffmpeg command before it's run.

  Every time that I run the encode, the MKV reports that the duration is 1195 hours and change, where it's supposed to be around 2 hours, plus some change. If I encode without the hard-coded subtitles, things turn out alright.

  Here's the command that's run, with the latest ffmpeg:

  ffmpeg.exe -probesize 50M -analyzeduration 100M -i "D:\Video\in.mkv" -c:a aac -ac 6 -strict -2 -async 1 -c:v libx264 -crf 20 -r 24000/1001 -s 1920x1080 -aspect 16:9 -pix_fmt yuv420p -preset fast -partitions default  -b-pyramid 1 -weightb 1 -8x8dct 1 -fast-pskip 0 -direct-pred 1 -coder ac -trellis 1 -me_method hex -subq 6 -me_range 16 -bf 3 -b_strategy 1 -refs 3 -flags +loop -sws_flags fast_bilinear -sc_threshold 40 -keyint_min 24 -g 48 -qmin 3 -qmax 51 -qdiff 4 -filter_complex "[0:v][0:s:2]overlay[out]" -map [out]  -map 0:a:0 -sn -y "D:\Video\out.mkv"
  

  I've tried a couple other MKV's with the same results. Anyone else run into this or know what's going on?

• Why is the resulting clip of my ffmpeg concatenation much longer than expected ?

  21 mai 2018, par joeycato

  I'd like to extract a set of clips from a 60fps input video, change each of their durations, then recombine those modified clips. Unfortunately when I attempt this, the resulting clip doesn't exactly match the sum of those durations.

  Here's my repro case:

  1. Extend an extracted 2-second clip to 4 seconds ( input frame count = 120 = 60fps * 2 sec ) )

  ffmpeg -y -ss 8 -t 2 -i ./clip_60fps.avi -filter:v "settb=(4/120),setpts=(4/120)*N/TB" -r 120/4 -vcodec huffyuv step1.avi

  2. Shorten an extracted 4-second clip to 1 second ( input frame count = 240 = 60fps * 4 sec )

  ffmpeg -y -ss 10 -t 4 -i ./clip_60fps.avi -filter:v "settb=(1/240),setpts=(1/240)*N/TB" -r 240/1 -vcodec huffyuv step2.avi

  3. Concatenate the modified clips:

  mylist.txt contents:

  file './step1.avi'
  file './step2.avi'
  

  ffmpeg -y -safe 0 -f concat -i ./mylist.txt -r 60 -vcodec huffyuv steps_joined.avi

  The result:

  ffmpeg -i step1.avi 2>&1 | grep Duration
  ffmpeg -i step2.avi 2>&1 | grep Duration
  ffmpeg -i steps_joined.avi 2>&1 | grep Duration
  

  Duration: 00:00:04.00, start: 0.000000, bitrate: 3228 kb/s

  Duration: 00:00:01.00, start: 0.000000, bitrate: 23132 kb/s

  Duration: 00:00:39.98, start: 0.000000, bitrate: 910 kb/s

  Why am I not getting an exact result of 5 seconds, but instead a much larger value?

• Rendering a remote raw h264 video stream in javascript using WebRTC [on hold]

  20 mai 2018, par Shahabi

  I'm new in Video streaming and decoding for rendering on Web Browser. My plan is to create a raw h264 stream on localhost environment and in Nodejs application, I want to read the raw h264 stream and render it on Web browser with Low latency.

  For creating a stream, I'm using VLC Stream option in h264 format on HTTP server. I'm using my laptop webcam and mic for streaming audio/video on localhost environment.

  Now I'm stuck on getting that stream on web page and render it on Web browser. I want to use WebRTC or any other opensource library for fast rendering.

  Anyone know or guide me into the right direction where i can solve my problem as mention above?

  Thanks

• FFmpeg Logo error

  20 mai 2018, par AniEncoder

  I tried to below code but it gives me error

  ffmpeg -i 1.mkv -i 1.png -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2" -codec:a copy 1.mkv
  pause
  

  Gives Only 2s video output