How to reduce RTSP streaming delay.

[K_AA]

Hello!

I develop an Qt application that can capture video from webcam and stream it using RTSP. On the other side my app receive video stream.
But I noticed a stable delay about 3-4 seconds. Does anybody know how to reduce this lag?

Code for video capturing and streaming.

Code: Select all

m_vlcInstance = libvlc_new(0, NULL); libvlc_vlm_add_broadcast(m_vlcInstance, "mybroadcast", "dshow://", "#transcode{vcodec=h264,vb=0,scale=0,acodec=mp4a,ab=128,channels=2,samplerate=44100}:rtp{sdp=rtsp://:5544/}", 0, NULL, TRUE, 0); libvlc_vlm_play_media(m_vlcInstance, "mybroadcast");

Code for video stream receiving.

Code: Select all

inst = libvlc_new (0, NULL); m = libvlc_media_new_path (inst, "rtsp://127.0.0.1:5544/"); mp = libvlc_media_player_new_from_media (m); libvlc_media_release (m); libvlc_media_player_set_hwnd (mp, ui->widget->winId()); libvlc_media_player_play (mp);

[Jean-Baptiste Kempf]

Decrease the caching.

[paulraj85]

Hi,

Iam trying to stream a video from IP camera using RTSP and displaying the video in a mfc application using libvlc. There is a delay upto 2sec in my application, Is there any way to reduce the delay?

In vlc player Tools->Preferences->Input/codecs, I choose Live555 stream transport to RTP over RTSP and changed Default Catching policy to Lowest Latency. By choosing this setting I can see the video delay is reduced in VLC player compare to my application.

Kindly help me how to make these settings through the code
Thank You

[Jean-Baptiste Kempf]

--network-caching is the option you need

[Rahul29]

Hi,

I am also facing the same problem. I am streaming a video from IP camera using RTSP and displaying the video in a Qt application using libvlc. There is a delay upto 2sec in my application, Is there any way to reduce the delay?

I have tried passing :network-cashing=200 to my URL but it doesn't work.

rtsp://admin:admin@192.168.253.99:554/cam/realmonitor?channel=1&subtype=0&unicast=true :network-caching=200

looking forward to some help.

Thanks

[Jean-Baptiste Kempf]

Do you have the same delay in VLC?

[Psykomusic]

Hi !
I'm trying the same thing, using LibVlc for a QtApplication in way to be cross-platform ios and android. I'm able to play the RTSP stream from an ipCamera but there a big delay (few seconds) and this delay is less important in the VLC app. I tried to reduce the network-caching but with this solution I drop too much frames and freezes appear.
With the logs I can see that lot of picture are late and not display.
In fact I have 2 messages :
avcodec decoder: More than 4 late frames, dropping frame
core video output: picture is too late to be displayed (missing 3237 ms).
Maybe have you some solution for this problem to.

I'm not fluent english and I know your french, there is the french message.

En fait j'utilise LibVlc pour une appli en Qt/Qml que j'utiliserai sur platforme mobile et desktop. Je suis déjà capable de récupérer les stream en bonne qualité mais avec un delay. Lorsque je diminue le Network-caching j'ai alors beaucoup de frames qui sont lachées et cela ajoute de la saccade à ma vidéo (en plus d'avoir toujours un peu de delay). A moins d'avoir un cache de 1000ms je drop beacoup de frame et j'ai des freeze. Avez-vous une solution pour ce type de problème ?

[Jean-Baptiste Kempf]

Et VLC s'en sort mieux?

[Psykomusic]

Hi, thx for your answer
Yes vlc is much better than my app using libvlc

[Jean-Baptiste Kempf]

Same version of VLC and libVLC?

[cdf1982]

Hi! I'm also doing some tests with the "--network-caching" option, and I wonder what's the default value for RTSP streams when the option is not specified.

[Rémi Denis-Courmont]

The default value is 1 seconds, but that probably doesn't mean what you think it does.