[Libav-user] Encoding packetization speed

jan hölscher jan.hoelscher at codergrid.de
Sun Sep 18 17:59:58 CEST 2011


You an try to set rc_lookahead=0, that should solve the delay.
Regards,
Jan.
Am 15.09.2011 04:37 schrieb "김희숙" <hskim095 at naver.com>:
> After decoding on another PC(192.168.1.100), I can see the delay 2 seconds
more. There is no exact calculation.
> The decoding module is also ffmpeg library.
>
> I found out ffmpeg encoder does not return output data even though vfw
capture data exist.
> After ffmpeg encoder is received more than 40 frames, the encoder returns
output data.
>
> BTW, I added cqp option and then the ffmpeg encoder returns output data
promptly.
>
> -----Original Message-----
> From: "NEERAJ SHUKLA"<neeraj2009shukla at gmail.com>
> To: "This list is about using libavcodec, libavformat, libavutil,
libavdevice and libavfilter."<libav-user at ffmpeg.org>
> Cc:
> Sent: 11-09-10(토) 02:14:35
> Subject: Re: [Libav-user] Encoding packetization speed
> 2011/8/31 김희숙 <hskim095 at naver.com>
> Hi All,
>
> I'm testing FFMPEG performance with libx264 for H.264 encoding.
> I found there may 2 or 3 seconds delay on receiving PC.
>
> The command is as follows:
> ffmpeg -r 30 -f vfwcap -s 1280x720 -i 0 -vcodec libx264 -b 2000k -minrate
1000k -coder 0 -flags +loop+cgop -cmp +chroma -partitions
-parti8x8+parti4x4+partp8x8-partp4x4-partb8x8 -me_method dia -subq 3
-me_range 24 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71
-b_strategy 1 -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -directpred 1 -flags2
+fastpskip -refs 6 -subq 5 -f rtp rtp://192.168.1.100:40000
>
> I also tested cif resolution and I got same result, 2 or 3 seconds delay.
> I captured the rtp packets and I found there is no many packets to be sent
on receiving side.
>
> In general, how many packets to be sent under 1280x720 at 30fps?
>
> the decoding picture quality was good but there was delay.
>
> I wonder there is missing point on above command or something.
>
> Please advise something to me.
>
> Thanks
> hsk
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/libav-user
> HOW ARE YOU CALCULATING THE DELAY ??
> PLEASE SPECIFY ELABORATELY
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