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Cannot read a 10-bit, 3-channel encoded video file as 10-bit

asked 2014-02-03 17:23:55 -0500

Nate gravatar image

updated 2014-02-04 10:07:02 -0500

Hello all,

I'm running into a problem reading a 10-bit, 3-channel encoded video that was saved from a high definition camera we have. I checked the file using GSpot, and it is encoded using the "Optibase VideoPump 10-bit 4:2:2 Component Y'CbCr" codec (v210).

I can read in frames using OpenCV's VideoCapture class from the file. I can even display the frames just fine using OpenCV's imshow function. Unfortunately, the cv::Mat object that the frames are saved into is of an 8-bit type (CV_8UC3).

Here is the code that I am using to read the video file:

   std::cout<< "Attempting to open file:  "<< filename<< std::endl;
   cv::VideoCapture videoIn; filename);
   if( !videoIn.isOpened())
      throw "Error when reading stream!";

   if( ! frame))
      return 0;

   int type= frame.type();  // Returns 16 (CV_8UC3)

Like I said earlier, frames are being read and displayed, but when I check frame.type(), it returns 16 (CV_8UC3). Since I am trying to get the extra precision by using 10-bits, this is suboptimal.

Does anyone know how to actually read the frames at 10-bit?



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What about using:


It is 16 bits big or 6 bit bigger than 10, and it is 3 channels.

keghn gravatar imagekeghn ( 2014-02-04 15:34:40 -0500 )edit

Thanks for the feedback keghn! I would love for it to read in as CV_16UC3. At 10 bit, that's actually what I would expect. Unfortunately, there does not seem to be a way to instruct the VideoCapture object to do that. At least not that I have found.

Nate gravatar imageNate ( 2014-02-04 23:41:24 -0500 )edit

You would like to have an option like the CV_RETRIEVE_ANY_DEPTH option in the imread fuction... Doesn't the source code of the VideoCapture interface uses the imread function on a certain moment? You might be able to change it there and rebuilt it yourself.

StevenPuttemans gravatar imageStevenPuttemans ( 2014-02-05 03:54:55 -0500 )edit

Thanks for the suggestion StevenPuttemans! I've not dug into the inner workings of OpenCV before. I'll have to download the source code and have a look at the internals of VideoCapture later today.

Nate gravatar imageNate ( 2014-02-05 10:04:45 -0500 )edit

Well, I downloaded the OpenCV source code and tried to figure out if there was some internal setting for VideoCapture that I could set to get it to read 10-bit video files. I couldn't find any reference to a "CV_RETRIEVE_ANY_DEPTH" setting, but the OpenCV source does have CV_LOAD_IMAGE_ANYDEPTH and IMREAD_ANYDEPTH preprocessor directives. Unfortunately, I could not track down where, if at all, these preprocessor directives might be used in VideoCapture. VideoCapture seems like it is a wrapper on top of IPL calls. Quite frankly, without a detailed system architecture diagram and writeup for OpenCV's video processing system, figuring this out is quite beyond me. At this point, I have to conclude OpenCV is not the right tool for reading and processing high-bitrate video files.

Nate gravatar imageNate ( 2014-02-06 10:53:13 -0500 )edit

Of course, if anyone has any alternative tools to OpenCV that might be viable, please post and let me know!

Nate gravatar imageNate ( 2014-02-06 11:08:33 -0500 )edit

Yeah digging into this is indead quite hard. You could however add a feature request on the development forum of openCV. It might encourage someone who has an idea to implement this feature.

StevenPuttemans gravatar imageStevenPuttemans ( 2014-02-07 01:50:30 -0500 )edit

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answered 2014-02-28 09:53:06 -0500

Nate gravatar image

Alright, so I didn't get direct 10-bit video reading in OpenCV working per se, but I did get a complicated, "hacky" solution that worked well enough to test whether the extra bit depth going from 8-bit video to 10-bit video was helpful.

So here is what I did:

  1. Used FFMPEG to convert the (10-bit) video from a v210-encoded AVI file into a series of (16-bit) PNG image files, one image file for each frame of the video. Obviously, this takes a tremendous amount of hard drive space. The 10-bits in the original seems to have been stretched to the 16-bit (I assume by adding 6 zero bits of padding to the end).
  2. Read the 16-bit PNG files in sequentially and process them as if they were frames in a video. They actually get read in a CV_16UC3 images!

And that's how I did it. This solution is ugly, hacky, and slow, but it worked.


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Hmmm this is indeed a 'hacky' way. Someone should add this to the videoWriter directive. Care to create a bug report at the dev forum?

StevenPuttemans gravatar imageStevenPuttemans ( 2014-03-10 07:27:14 -0500 )edit

answered 2015-01-07 14:46:07 -0500

Hi Nate!

I had the same problem, and I created a solution using OpenCV's functions. Do you want know the solution, or this problem is no longer important? In my case, I received raw data (uncompress video, and the data was in an array of char) from multiples camera feeds (this scenario involved channels Y, U and V separated, different values of chroma subsampling and different values of bit rate). When the Bit Depth was equal to 10-bit I had problems with OpenCV. Using cv::Mat( int height, int width, CV_16UC, (unsigned char*) feed_channel_Y) i didn't had a successful results. In my opinion i think if you use the function cv::VideoCapture, you won't get good results.

To get a solution for this problem, I made some conversions on video data. But remember I worked with uncompressed video data, the video didn't have any codec.

Cheers, Victor

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Thanks for the information Victor!

This problem is no longer important to me--I was simply trying to check out if 10-bit video would provide useful extra information for a specific problem. After running my hacky solution, it turned out it wasn't worth pursuing further.

Glad you were able to find something that worked though! This was an annoying problem. :o)


Nate gravatar imageNate ( 2015-01-29 12:50:41 -0500 )edit
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Asked: 2014-02-03 17:23:55 -0500

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Last updated: Jan 07 '15