[FFmpeg-user] ffmpeg stdout write performance on windows (buffering request)

Jason Anders jgo at kataf.nl
Thu Aug 16 21:19:03 CEST 2012

I'd like to update this RFE to status: discard :o)

It turned out that reading stdin is dog slow when trying to do this:
    read(handle, buffer, w*h*3);

I rewrote it to read from stdin in batches of 64K, and-a-bit until I get a 
full frame. After this minor change I could read frames in 8ms, as opposed 
to the ~330ms I had earlier.

Thanks for your time, I'll crawl back to where ever I came from!

 - Jason

----- Original Message ----- 
From: "Roger Pack" <rogerdpack2 at gmail.com>
To: "FFmpeg user questions" <ffmpeg-user at ffmpeg.org>
Sent: 16 August 2012 20:38
Subject: Re: [FFmpeg-user] ffmpeg stdout write performance on windows 
(buffering request)

>> At 1280x544 @ 24fps, using RGB8 as output means we're moving around
>> 48MB/sec. I suspect that ffmpeg is writing relatively small batches of 
>> data
>> to stdout. As said, it works perfectly fine on Linux, but unfortunately
>> we're not as lucky on Windows.
> I've heard of this before, so you're probably right.
> Just how to buffer the output I have no idea.
> In the meantime you could try writing to a windows named pipe, or to a
> file.  Or submit a patch :)
> -r
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.2197 / Virus Database: 2437/5203 - Release Date: 08/15/12

More information about the ffmpeg-user mailing list