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• Normalizing with ffmpeg-normalize, slight variations in sound

  20 mai 2022, par Antti Rytsölä

  I have some flacs which I am trying to normalize for Spotify and Distrokid.

  


  I got the guide from this post

  


  ffmpeg-normalize inbound/*.flac -t -14 -lrt 11 -tp -1 -ext flac -c:a flac -of normalized/


  


  Now the problem is ( before submitting to Distrokid ) that when listening to normalized versions there seems to be light deviations, like muffling, to the sound at half a second lenghts.

  


  Small sample, towards the end.

  


  Now I'm asking for help because even though I can try different settings I still want to conform to Spotify normalization guide.

  


  The Spotify guide is as follows :

  


  Target the loudness level of your master at -14dB integrated LUFS 
and keep it below -1dB TP (True Peak) max. This is best for lossy 
formats (Ogg/Vorbis and AAC) and makes sure no extra distortion’s 
introduced in the transcoding process.

If your master’s louder than -14dB integrated LUFS, make sure 
it stays below -2dB TP (True Peak) to avoid extra distortion. This 
is because louder tracks are more susceptible to extra distortion 
in the transcoding process.


  


  and

  


   ffmpeg version N-102727-g580e168a94-tessus
 ffmpeg-normalize v1.22.8


  


  Tracks now on Spotify.

  


• ffplay startup time proportional to specified framerate

  17 décembre 2019, par bremen_matt

  I am playing a video over http using ffplay. The call I am using looks like this :

  ffplay -framerate 30 -fflags nobuffer -flags low_delay -autoexit -i http://localhost:8880

  The video is an H.264 encoding where (my understanding is a bit unclear here) it is something like a "raw" H.264 stream without timestamps.

  My primary concern is to get video displayed with low latency. In that regard, the video is fine.

  The issue is with the framerate and with the startup time.

  The video source is emitting frames as soon as they are processed, so the frame rate is not constant. However, my experience is that as long as you specify a framerate larger than the max achievable frame rate of the source, then the viewer still looks fine. On the flipside, if the video source starts emitting frames at 60 fps, but I specify a framerate of 30, then the delay just sort of builds up in ffplay to the point where after 10 seconds, the video is 20 seconds behind. So the first question would be whether there is a way to get ffplay to use a variable framerate. The behavior I am looking for is "display a frame as soon as it is received over http".

  In light of the aforementioned issue, the approach I have been taking is to simply specify a high framerate, which seems to work. However, there is an issue with this approach in the form of startup time. When I set the framerate to 10, the ffplay window starts in approx 3 seconds, but then quickly starts accruing a lag (so I can’t do this). When I set the framerate to 100, the ffplay window takes 30 seconds (literally 30 seconds) to start, but then will not have any lag.

  I have seen that ffmpeg has a vsync option that on the surface seems like it would allow you to set a variable framerate. However, ffplay doesn’t seem to recognize this. I would also be willing to pipe the output of ffmpeg to a different window (I am running Ubuntu 18.04) if that is what must be done, but I would prefer not to have to recompile ffplay.

• Saving highest quality video from video-capture card

  23 décembre 2013, par DusteD

  I have a machine with 2x3 3ghz dual-core xeon and 4x10krpm scsi 320 disks in raid0.
  The capture card is an osprey 560 64 bit pci card.
  Operating system is currently Windows Server 2003.

  The video-stream that I can open with VLC using direct show is rather nice quality.
  However, trying to save this video-stream without loss of quality has proven quite difficult,
  using the h264 codec I am able to achieve a satisfying quality, however, all 4 cores jump to 100% load after a few second and then it start dropping frames, the machine is not powerful enough for realtime encoding. I've not been able to achieve satisfying mpeg1 or 4 quality, no matter which bitrate I set..

  Thing is, the disks in this machine are pretty fast even by todays standard, and they are bored.. I don't care about disk-usage, I want quality.
  I have searched in vain for a way to pump that beautiful videostream that I see in VLC onto the disk for later encoding, I reckon the disks would be fast enough, or maybe something which would apply a light compression, enough that the disks can keep up, but not so much as to loose visible quality.

  I have tried FFMPEG as it seems capable of streaming a yuv4 stream down to the disk, but ofcause FFMPEG is unable to open the dshow device ( same error as this guy Ffmpeg streaming from capturing device Osprey 450e fails )

  Please recommend a capable and (preferably) software which can do this.