使用OpenCV VideoCapture读取视频文件

Question

I am having trouble being able top open any video files in OpenCV besides those encoded in MJPEG.

I have installed OpenCV using this script (which should compile OpenCV with support for ffmpeg) and an testing using the sample provided here .

When running with a h264 encoded video I get:

[mov,mp4,m4a,3gp,3g2,mj2 @ 0x123ed80] multiple edit list entries, a/v desync might occur, patch welcome
[h264 @ 0x12465e0] A non-intra slice in an IDR NAL unit.
[h264 @ 0x12465e0] decode_slice_header error
Could not open the output video for write: test.mp4

When running with an MPEG-2 encoded video I get:

[mpegts @ 0x1e92d80] PES packet size mismatch
[mpegts @ 0x1e92d80] PES packet size mismatch
[mpegts @ 0x1e92d80] max_analyze_duration reached
[mpegts @ 0x1e92d80] PES packet size mismatch
Could not open the output video for write: test.mpeg

I am running x64 Ubuntu 12.04.

EDIT: I tried OpenCV 2.4.8 on a Ubuntu 13.10 x86 VM, ffmpeg works fine, however the sample code still fails, this time with the following error:

[h264 @ 0x849ff40] A non-intra slice in an IDR NAL unit.
[h264 @ 0x849ff40] decode_slice_header error
Could not find encoder for codec id 28: Encoder not foundOpenCV Error: Unsupported format or combination of formats (Gstreamer Opencv backend doesn't support this codec acutally.) in CvVideoWriter_GStreamer::open, file /home/dan/Install-OpenCV/Ubuntu/2.4/OpenCV/opencv-2.4.8/modules/highgui/src/cap_gstreamer.cpp, line 505
terminate called after throwing an instance of 'cv::Exception'
  what():  /home/dan/Install-OpenCV/Ubuntu/2.4/OpenCV/opencv-2.4.8/modules/highgui/src/cap_gstreamer.cpp:505: error: (-210) Gstreamer Opencv backend doesn't support this codec acutally. in function CvVideoWriter_GStreamer::open

Answer 1

I am not sure about the main reason for this. But I guess this problem is relate to the decoder installed on your system. According to the install script from github, it removes your ffmpg and x264 then rebuilds them from source code. Before testing your OpenCV code, try simple "ffmpeg" command on your test video. Such as: ffmpeg -i inputfile.avi -f image2 image-%3d.jpeg

Answer 2

1. The script you have used is quite old and installs old version of OpenCV (2.4.2, while the latest stable is 2.4.8), try to use this script - https://github.com/jayrambhia/Install-OpenCV/blob/master/Ubuntu/2.4/opencv2_4_8.sh or install OpenCV and ffmpeg on you own.
2. As rookiepig mentioned - check whether ffmpeg is working.
3. Try to use different codec - here http://www.fourcc.org/ is full list of options, of course testing all of them is useless - jsut try the most popular codecs.
4. I know that it's stupid, but on Windows some codecs works only in release mode(okay, probably they are working in both modes, but on my machine they used to work only in release mode). Try to compile you program in both modes and check whether there is some difference.

And show us you code, maybe there is something wrong in it.