[FFmpeg-user] Request for advise on performance - transcoding on the fly

[Charu Palkar]

Hi Shawn,

But what about the buffering issue I see with XMBC with the same same 
transcoding.

Any explaination for that ?

Thanx

Charu
--



----- Original Message ----
From: NokNok Developer <developer at noknok.net>
To: ffmpeg-user at ffmpeg.org
Sent: Sun, May 1, 2011 9:06:35 PM
Subject: Re: [FFmpeg-user] Request for advise on performance - transcoding on 
the fly

Neither of those streams you are doing are "live transport" streams.

For example the WD LIVE stops because when it issues its 1st GET, it 
also gets the CURRENT size of the file, at that point in time, and then 
thats all it asks for.  You need to use a live streaming container/player.

eg: HLS (Apple M3U8), or FLV with Flash Player, or ASF Streaming, etc.  
There are other approaches, as to streaming in chunked http, etc.

Shawn

On 5/1/2011 7:27 PM, Charu Palkar wrote:
> Hi,
>
> I am new to the forum and would like guidance.
>
> System :
>      Server : Rackable
>      CPU :  AMD Opteron  (2GHZ) Dual CPU
>      RAM : 2 Gb
>      Disk  : SATA  ( 250GB x 4 disks )  -  3 disks configured as RAID0  
(3Ware)
>      Network :  1 Gig
>      OS : Slackware - 13.1
>
> Command :
>        ffmpeg -benchmark -i
> /mnt/samba/share/test/Baraka.1992.BRrip.H264.AAC.ITS-ALI.mp4 -threads 4 
-target
> ntsc-dvd -aspect 16:9 test.mpg
>
> NOTES :
>        Only one CPU has 90% (sys + user),  others 4% (sys + user),  no wait on
> I/O
>        There is no swapping, initial page faults is 11 and remains constant 
for
> the entire time
>        Both files input and output are located on the RAID partition
>        The time it takes to transcode is 20% higher than the run-time of the
> media file
>        Nothing else is running on the server
>        ffmpeg - Built with ARCH=x86_64  CPU=opteron
>
> QUESTIONS :
>        Q : What else can I do to speed up the transcoding  to take less time 
>than
> run-time of media file ?
>                  + To use for on-the-fly transcode with a media server.
>
>        Background : Installed media server  'serviio' and transcoding
> on-the-fly-enabled. The following command is invoked.
>
>                            ffmpeg -i
> /mnt/samba/share/test/Baraka.1992.BRrip.H264.AAC.ITS-ALI.mp4 -y -threads 4
> -vcodec mpeg2video
>                                      -sameq -r 23.976 -g 15 -copyts -acodec 
ac3
> -ab 192k -ac 6 -map 0:0 -map 0:1 -sn -f mpegts
>
>  /mnt/samba/trans_tmp/Serviio/transcoding-temp-2-MPEG2TS.stf
>
>                            CPU Usage is 60% per core and no wait on I/O,
> swapping.
>
>                            Viewing using WDTV Live  streaming stops after 31
> secs consistently
>                            Viewing using  XMBC on WinXP  stream starts 
>buffering
> after  7 mins or 3 mins of play, takes about 8 to 10 seconds to catch up
>                            Cabled network 100 MB connection on WinXP the 
>network
> usage varies between  7% to 50%
>
>        Q : What can be done to make transcoding on-the-fly continuous ?
>
> Any and all help is greatly appreciated.
>
> Thanx
>
> Charu Palkar
> --
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> ffmpeg-user at ffmpeg.org
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