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is there a way to speed up transcoding for offline file?
Posted: 06 Mar 2010 14:49
by socialjazz
I am converting an offline file from one format to another. Is there a way to speed up the conversion. I have tried using input.rate variable but it does not help.
Re: is there a way to speed up transcoding for offline file?
Posted: 06 Mar 2010 20:03
by Rémi Denis-Courmont
If you are not rendering the file, VLC transcodes as fast as the CPU and bus can. There is no speed setting.
Re: is there a way to speed up transcoding for offline file?
Posted: 08 Mar 2010 15:47
by socialjazz
I am using windows with VLC 1.0.5
Using the sout parameter:
vlc -vvv "c:\source.avi" --sout=#transcode{vcodec=mp4v,acodec=mp4a,ab=192,channels=2}:standard{access=file,mux=mp4,dst="c:\converted.mp4"}
makes the vlc transcode at 1x speed. Trying other codecs does the same.
What Option string are you using to convert media file at maximum speed?
Re: is there a way to speed up transcoding for offline file?
Posted: 08 Mar 2010 16:48
by Rémi Denis-Courmont
It's automatic. There is no way to enable or disable it manually. And by the way, transcoding video is slow. No big news here.
Re: is there a way to speed up transcoding for offline file?
Posted: 04 Oct 2011 19:55
by tapif
sorry to bring up such an old topic.
Is there any way, on the other side, to read from a file as if it was a live content, in order to force the output to 1x?
Re: is there a way to speed up transcoding for offline file?
Posted: 04 Oct 2011 21:36
by Rémi Denis-Courmont
On Linux or almost any other Unix system, you can try this but it will be flaky:
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cat YOUR_FILE | vlc stream:///dev/stdin
You really should let the player autodetect this. Anyhow, if the output requires pacing, pacing will be enabled.
Re: is there a way to speed up transcoding for offline file?
Posted: 05 Oct 2011 00:33
by tapif
actually my command line is something like
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$ vlc -I dummy "filename" --sout='#transcode{vcodec=h264,venc=x264{vbv-maxrate=400,vbv-bufsize=400,qcompatetol=0, bitrate=400},vb=400,acodec=mp4a,ab=32,scale=1,channels=2,deinterlace,audio-sync}:std{mux=ts,dst=-}' vlc://quit
I haven't tried `cat` but the problem is I would like either the input, the transcoder or the output to be limited to 1x, in order to have into stdout every time instant the 'up to time' output without rendering it on screen.
I'm trying to achieve this so to lower CPU load, as well as to be able to chunk the content properly.
I've found a similar constaint in ffmpeg ('re' flag at command line) but I don't think it's usable in/from vlc
Re: is there a way to speed up transcoding for offline file?
Posted: 04 Mar 2012 18:20
by Nwest
A way to speed up transcoding a little bit is to have your original files, the ones to be transcoded, on a seperate hard drive such as an external USB hard drive. This way, the external hardrive is only reading the original files and feeding them into your computer while your computer's hard drive is only occupied with transcoding and writing the transcoded files. Your computer's hard drive will not have to spend time both reading the original files and writing the transcoded ones.