I'm using FFMPEG to decode video stream from IP Camera, I have the example code that can decode video stream with any codec into YUI frames format.
But my case is special, I will describe as below
The IP camera stream is MJPEG, and I want using FFMPEG to decode, but I don't want to decode frame into YUV, I want to decode frame under jpeg format, and save those jpeg buffer into image files (*.jpg).
So far, I can do it by converting YUV frame (after decoding) to Jpeg, but this will cause bad performance. Since video stream is MJPEG, I think I can get jpeg data before decoding to YUI, but I don't know how to do it.
Someone can help me?
Many thanks,
T&T
Related
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 coded an encoder using FFMPEG (c++). The requirements for this encoder are:
The output format should be uncompressed avi,
Preferably using RGB24/YUV444 pixel format since we do not want chroma subsampling.
Most standard players should support the format (windows media player (WMP), VLC)
Using the encoder I wrote, I can write a number of file types right now:
Lossless H.264 encoded video using the YUV420p pixel format and AVI container. (Obviously not uncompressed and chroma subsampled, however both WMP and VLC play without any problem.)
MPEG4 encoded video using the YUV420p pixel format and AVI container.(Obviously not uncompressed and chroma subsampled, however both WMP and VLC play without any problem.)
AYUV encoded video using the YUVA444P pixel format. (uncompressed as far as I understand and not chroma subsampled. However, VLC does not play this.)
FFV1 encoded video using the YUV444P pixel format. (lossless, and not chroma subsampled. However, WMP does not play this.)
The above is derived from this very usefull post.
So I am now looking into the RAWVIDEO encoder from FFMPEG. I can't get this to work and neither can I find an example in the FFMPEG documentation on how to use this encoder for writing video. Can somebody point me in the right direction or supply sample code for this?
Also, if there is another direction I should follow to meet my requirements feel free to point me to it.
Thanks in advance
I am trying to decode a h264 video that I encoded using FFMPEG. The encoder used is libx264rgb with a AV_PIX_FMT_BGR0 pixel format. The encoded video plays well inside ffplay.
When I decode the frames, I obtain a planar pixel format(AV_PIX_FMT_GBRP) which is different from the original. Is it normal? If yes is there a way to disable the planar format? (either at encoding or decoding). This would allow me to skip the packing overhead from planar at runtime.
I used this decoder sample with a AV_CODEC_ID_H264 decoder instead of AV_CODEC_ID_MPEG1VIDEO.
Thank you!
I use live555 to receive RTP video frame (frame encoded in H264). I use Live555 open my local .sdp file to receive frame data. I just saw DummySink::afterGettingFrame was called ceaselessly。 if fReceiveBuffer in DummySink is correct, Why FFMPEG cannot decode the frame? My code is wrong?
Here is my Code Snippet:
http://paste.ubuntu.com/12529740/
the function avcodec_decode_video2 is always return failed , its value less than zero
fReceiveBuffer is present one video frame？
Oh, Here is my FFMPEG init code need to open related video decoder:
http://paste.ubuntu.com/12529760/
I read the document related H264 again， I found out that I-frame(IDR) need SPS/PPS separated by 0x00000001 insert into the header and decoder have a capacity to decode the frame correctly. Here is a related solution
FFmpeg can't decode H264 stream/frame data
Decoding h264 frames from RTP stream
and now, My App works fine, it can decode the frame and convert it to OSD Image for displaying to screen .
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?