[FFmpeg-trac] #4155(ffmpeg:new): UDP Output is Waving
FFmpeg
trac at avcodec.org
Wed Dec 3 23:27:54 CET 2014
#4155: UDP Output is Waving
-------------------------------------+-------------------------------------
Reporter: | Type: defect
smallishzulu | Priority: normal
Status: new | Version:
Component: ffmpeg | unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug (not sure if a bug):
I use a valid TS file and use below command:
ffmpeg -re -i test.ts -c:v copy -c:a copy -vb 2500k -minrate 2500k
-maxrate 2500k -bufsize 5000k -muxrate 2500k -flush_packets 0 -f mpegts
udp://225.2.1.1:1234?pkt_size=1316
FFmpeg version is 2.4.3 (not a nightly git version)
I traceout UDP packets using tcpdump and I see constant UDP traffic
output:
11:41:14.306157 IP 172.31.35.47.43299 > 225.2.1.1:1234: UDP, length 1316
There is a Window PC in the network and using Wireshark, I can see Windows
PC receives 1472 bytes payload. Also constant.
I replaced Windows PC with a Linux PC and I traceout the traffic and I
found also constant receive of UDP packets in 1316 bytes.
However, I monitored the traffic over a Mikrotik router and I watched the
network graphic of this UDP packets, they are waiving, not constant.
I removed the Mikrotik router and plugged a Windows PC directly to FFmpeg
output server and I traced network traffic using StreamXpert, I see
traffic is waiving again.
If I generate a UDP multicast traffic using iperf, i see constant UDP
traffic on Mikrotik router.
I dont know why but FFmpeg UDP multicast output is 1316 bytes but there
maybe a problem with output timing, which I mean is output is not
constantly 2.5Mbps
Please see attached image file. On each run of same command, output
graphic slightly varies/changes.
Am I doing something wrong or is there a bug?
(Extra note: If I pipe out same output to an ASI card instead of UDP
stream, output Mbps is constant as well.)
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Ticket URL: <https://trac.ffmpeg.org/ticket/4155>
FFmpeg <https://ffmpeg.org>
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