I received some video data via RTP / RTSP / SIP, the data is encoded by H264 and sent by a IP camera. I would like to convert H264 keyframe data into a picture and analyze whether it contains faces. I do not want to use FFMPEG such a huge library, just use libx264 and opencv can do it? How?
Thanks.
No, not possible. X264 can not decode (it is a h264 encoder only). It also can not encode jpeg/png. Ffmpeg is what you need. If it is too large, custom compile including only the features you need. And static link so unused functions are striped out.
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I've a 16bit greyscale video stream from a LWIR (thermal camera) and I want to forward the stream over RTP without any compression.
gstreamer format is: video/x-raw,format=GRAY16_LE,width=640,height=520,framerate=9/1
But I can't find any plugin to transmit the data over RTP.
https://gstreamer.freedesktop.org/documentation/rtp/index.html?gi-language=c
Do you have an idea?
Thanks, Martin
Check for the specs of uncompressed video data over RTP:
https://www.rfc-editor.org/rfc/rfc4175
As you will notice your specific format is not covered by the specification.
I am compressing frames coming from webcam with libx264. So far I used YUY2 raw frames and swscale to transcode the frames to I420, which is usable by x264.
Anyway I would like to add support for mJPEG webcams (usually webcam provides both, but mJPEG allows higher frame rates and resolutions). What can I use to transcode mJPEG to some format, that can be used by x264?
If you already use swscale why not to use ffmpeg/libav (libavcodec) for decoding mjpeg?
I use Live555 h.264 stream client to query the frame packets from an IP camera, I use ffmpeg to decode the buffer and analysis the frame by OpenCV.(those pipeline are based on testRTSPClient sample, I decode the h.264 frame buffer in DummySink::afterGettingFrame() by ffmpeg)
And now I wanna stream the frame to another client(remote client) OnDemand mode in real-time, the frame may added the analysis result(boundingboxs, text, etc), how to use Live555 to achieve this?
Well, your best bet is to re-encode the resultant frame (with bounding boxes etc), and pass this to an RTSPServer process which will allow you to connect to it using an rtsp url, and stream the encoded data to any compatible rtsp client. There is a good reference on the FAQ for how to do this http://www.live555.com/liveMedia/faq.html#liveInput which walks you through the steps taken, and provides example source code which you can modify for your needs.
How to transcode RGB images into VP8 frames (Keyframe + some dependent frames)?
So I created some images how to turn tham into VP8 now?
The easiest way to go is to use ffmpeg.
The latest release of ffmpeg (0.6) now supports the VP8 codec, and building it is now easy.
Then, ffmpeg makes it simple to gather individual frames into a movive. Here is a tutorial, but you can google for more results.
First, you need a codec library for VP8:
http://www.webmproject.org/code/build-prerequisites/
Using libvpx API you can then encode your RGB frames into VP8 frames.
I'm developing a DirectShow filter which has 2 input pins (1 for audio, 1 for video). I'm using libavcodec/libavformat/libavutil of FFMpeg for encoding the video to H264, audio to AAC and mux it/stream using RTP. So far I was able to encode video and audio correctly using libavcodec but now I see that FFMpeg seems to support RTP muxing too. Unfortunatelly, I can't find any example code which shows how to perform H264 encoding and RTP muxing. Does anybody know good samples?
Try checking out the code in HandBrake. Specifically, this file muxmp4.c, which was a jem I found working with FFMpeg / RTP. Be sure and use av_interleaved_write_frame() and the extradata fields correctly. Those were some key differences I remember for RTP.
Still, I had some stability issues with RTP/RTSP with FFMpeg, (I'm sure it's getting better). I had much better luck with live555, and you can look at the code in VLC and MPlayer for good examples on how to use it.