[FFmpeg-user] ATSC TS live transcode on DL360 G4?

Sun Feb 3 02:37:15 CET 2013

Hello Hank, Tom, and thanks for your advice. I did record half an hour 
ATSC mpeg2 stream into a file and tried to transcode it file-to-file. I 
also took the 'nice' out as anyway there is nothing else running, no 
need to prioritize this process. Results are below.

Input #0, mpegts, from 'out.ts':
   Duration: 00:55:52.35, start: 16712.311489, bitrate: 15655 kb/s
   Program 1
     Stream #0:0[0x44](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 
5.1(side), s16, 384 kb/s
     Stream #0:1[0x45]: Video: mpeg2video (Main) ([2][0][0][0] / 
0x0002), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 15000 kb/s, 59.94 fps, 60 
tbr, 90k tbn, 119.88 tbc
using cpu capabilities: MMX2 SSE2 SSE3 Cache64
profile Constrained Baseline, level 3.2
muxrate VBR, pcr every 6 pkts, sdt every 200, pat/pmt every 40 pkt
Output #0, mpegts, to 'video.h264':
   Metadata:
     encoder         : Lavf54.29.104
     Stream #0:0: Video: h264, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 
q=-1--1, 90k tbn, 60 tbc
     Stream #0:1(eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 
5.1(side), 384 kb/s

Results:
   A. -preset fast:
ffmpeg -re -i out.ts -acodec copy -vcodec libx264  -preset fast -s:v 
hd720 -f mpegts video.h264
top - 16:57:50 up 23 days,  3:33,  4 users,  load average: 5.81, 4.54, 
2.34

   B. -preset ultrafast:
ffmpeg -re -i out.ts -acodec copy -vcodec libx264  -preset ultrafast 
-s:v hd720 -f mpegts video.h264
top - 17:03:24 up 23 days,  3:39,  4 users,  load average: 4.16, 4.18, 
2.84

Computer is DL 360 G4 at 3.4Ghz. As seen we are 'almost there' with 
-preset ultrafast, just slightly on the other side of the border.

This is quite bad, as I need to transcode ~10 channels, and DL360 G4 is 
inexpensive and fast 64bit server. No luck, however.

I did try another ATSC channel, same result as above. So, it really 
looks that 2 Xeon 64 bit @3.4Ghz can not transcode real-time ATSC 
~20Mb/s to h264.

If you wish I can put the file  for download for yourself to test 
(6GB).

All the best, george

Le 2013-02-01 10:00, Henk D. Schoneveld a écrit :
> On Feb 1, 2013, at 3:20 PM, Subscriptions <subscriptions at znet.ca> 
> wrote:
>
>> Hello again,
>>
>> It simply looks that 2 double-core Xeon at 3.4Ghz (HP DL 360) can 
>> not transcode mpeg2 ts live stream coming at ~20 Mb/s to h264. Even 
>> with 'preset ultrafast' the load goes above 4 and the buffer overruns. 
>> The minimal processor that is able to do this up to now is a single 
>> Phenom 2 X6 Black at 3.4 Ghz, and it sometimes gets with load ~5 on 
>> it's six cores.
> It looks a bit odd to me. I can encode 2 DVB-S 1080i h264-based
> recordings to 720p with a 4-core i5-2500k not over clocked.
> If you remove the nice statement and add -re statement before your 
> source like
> ffmpeg -re -i udp etc should do the job. BTW. I do my encodings from
> a file, not from a stream. Maybe an intermediate file will help,
> although it adds a slight delay.
>
> Henk
>>
>> Thanks, George
>>
>>
>> Hello,
>>
>> I want to reduce bit rate of ~18Mb/s ATSC live stream which I 
>> capture over the air with HDHomerun box, and it looks that an HP DL360 
>> G4 server (two 64 bit double core Xeon processors) can not do the job. 
>> Is there some way to make this functional? My idea is to reduce the 
>> stream from 18Mb/s to about 4-5Mb/s at hd720. The problem is that 
>> processor load goes over 4 and starts to overrun the buffer. Is there 
>> a way to make the transcoding somehow work with x264 on that computer?
>>
>> Thanks, George.
>>
>> nice -n -20 ffmpeg -i 
>> "udp://239.255.254.1:1234?fifo_size=6000000&overrun_nonfatal=1&" 
>> -acodec copy -c:v libx264 -crf 22 -preset fast -f mpegts 
>> udp://239.255.254.240:1234
>>
>> ffmpeg version 1.0 Copyright (c) 2000-2012 the FFmpeg developers
>>  built on Oct 16 2012 09:46:44 with gcc 4.7 (Debian 4.7.2-4)
>>
>> Stream #0:0[0x31]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), 
>> yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 15000 kb/s, 63.81 fps, 59.94 
>> tbr, 90k tbn, 119.88 tbc
>>
>> using cpu capabilities: MMX2 SSE2 SSE3 Cache64
>> Output #0, mpegts, to 'udp://239.255.254.240:1234':
>>  Metadata:
>>    encoder         : Lavf54.29.104
>>    Stream #0:0: Video: h264, yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 
>> q=-1--1, 90k tbn, 59.94 tbc
>>    Stream #0:1(eng): Audio: ac3 ([129][0][0][0] / 0x0081), 48000 Hz, 
>> 5.1(side), 384 kb/s
>>
>>
>> Tasks:  82 total,   2 running,  80 sleeping,   0 stopped,   0 zombie
>> %Cpu0  : 96.3 us,  1.0 sy,  0.0 ni,  0.3 id,  0.0 wa,  0.0 hi,  2.3 
>> si, 0.0 st
>> %Cpu1  : 95.7 us,  1.0 sy,  0.0 ni,  1.0 id,  0.0 wa,  0.0 hi,  2.3 
>> si, 0.0 st
>> %Cpu2  : 97.7 us,  1.3 sy,  0.0 ni,  0.3 id,  0.0 wa,  0.0 hi,  0.7 
>> si, 0.0 st
>> %Cpu3  : 96.0 us,  0.7 sy,  0.0 ni,  2.0 id,  0.0 wa,  0.0 hi,  1.3 
>> si, 0.0 st
>> KiB Mem:   3995312 total,  2685548 used,  1309764 free,    74516 
>> buffers
>>
>> processor       : 3
>> vendor_id       : GenuineIntel
>> cpu family      : 15
>> model           : 4
>> model name      : Intel(R) Xeon(TM) CPU 3.40GHz
>>
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