Black screen for RTSP H.264 to H263 encoding

[Sebastian Dröge]

On Mi, 2013-11-27 at 06:15 -0800, buro1983 wrote:
> Hello, i've two queries
> 
> 1) i'm trying to encode rtsp video feed which is having h.264 codec, into
> h.263.
> 
> gst-launch-1.0 -v rtspsrc location="rtsp://source" ! capsfilter
> caps="application/x-rtp,media=(string)video,payload=(int)97,clock-rate=(int)90000,encoding-name=(string)H264"
> ! rtph264depay ! avdec_h264 ! videoscale ! videorate skip-to-first=true !
> videoconvert ! queue ! capsfilter
> caps="video/x-raw,format=(string)I420,width=(int)352,height=(int)288,framerate=(fraction)15/1,colorimetry=(string)bt601"
> ! avenc_h263p rtp-payload-size=10 ! rtph263ppay pt=96 ! udpsink
> clients="IP:Port"
>
> But i'm getting black screen while testing through vlc player. If any object
> in that video starts moving then only i'm getting visual of that particular
> object and remaining screen is black. I'm not able to figure out the issue.

You will have to wait at the receiver until a keyframe is received most
probably. Try setting a lower max-key-interval value on the encoder.

Also see this: https://bugzilla.gnome.org/show_bug.cgi?id=711257
With gst-rtsp-server you should be able to ensure that you always get a
keyframe as first frame received by a receiver. Not sure if RTSP is an
option for you though.

> 2) Few mobile handset is able to play QCIF but not CIF and few can play
> both. What encoding format will be good if I want to play my live video feed
> on all mobile handset.

Well, "all mobile handset" is a very wide range of devices. You probably
will have to provide multiple streams to make that work on all devices,
also not all devices support RTSP/RTP at all.

-- 
Sebastian Dröge <sebastian at centricular.com>
Centricular Ltd - http://www.centricular.com
Expertise, Straight from the Source
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