CODEWITHSUNDEEP
ffmpeg
ittay
ittay

Reputation: 689

A long delay (5-8 seconds) before ffmpeg receives first frame

I transmit video file and receive it. I see a very long delay before first frame is received, around 5-8 seconds:

::sender.bat
ffmpeg -re -i sample.mp4 -vcodec h264 -tune fastdecode -tune zerolatency -f mpegts udp://127.0.0.1:1234

::receiver.bat
ffmpeg -i udp://127.0.0.1:1234 -y output.mp4

Upvotes: 0

Views: 1159

Answers (3)

SergeyR
SergeyR

Reputation: 515

Try to use minimal -probesize 32 for the receiver (player). It worked for me.

probesize integer (input)
Set probing size in bytes, i.e. the size of the data to analyze to get stream information. A higher value will enable detecting more information in case it is dispersed into the stream, but will increase latency. Must be an integer not lesser than 32. It is 5000000 by default.

It works with option -tune zerolatency of mpegts or with matroska (simply -f matroska).

Upvotes: 0

ittay
ittay

Reputation: 689

I have found the answer, there is a -analyzeduration parameter which controls the amount of time needed to identify stream type. Default is 5 seconds , when I reduced it to 1 second (-analyzeduration 1000000), the movie started faster

Upvotes: 1

Gyan
Gyan

Reputation: 93048

It's due to the default x264 keyframe interval being long - 250 frames.

Keep it low. Add -g 25 for a 25 frame interval.

Also, it helps to start the receiver before the sender.

Upvotes: 2

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