Viewing YUY2 video in IJ
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Greetings,
I am currently using the Quicktime plugin to view live video from a USB camera. The data coming out of the camera is in YUY2 format....sort of (two bytes per pixel...but its a 12 bit camera output so we dropped the least 4 bits into the U byte). Using the Quicktime Capture scheme to view video, the code translates YUY2 into RGB.... and it is difficult to recover the U term. Is there a way to view video directly as YUY2? I tried the VirtualDub approach and IJ did not like it....was not able to open the AVI file. Even if it did work, you have to view/capture/save the video in VirtualDub first and then open IJ. I want to do it all in IJ. Any insight would be much appreciated. Thanks, Seth Pappas -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html |
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Hi Seth,
recent versions of ImageJ can open uncompressed YUV-based avi files with 12 bits/pixels (YV12, I420, NV12, NV21). If it is a different format, use ffmpeg to convert it to an YUY2-type format like NV12: ffmpeg -i infile.avi -pix_fmt nv12 -f avi -vcodec rawvideo outfile.avi To get the the Y and U bytes, you can take the AVI_Reader from the ImageJ source and modify it to get an external plugin (replace 'package ij.plugin;' by 'import ij.plugin.*;'. Then modify writeRGBfromYUV in a suitable way, e.g.: int r=u, g=y, b=v; the resulting image will have the raw u in the red channel, y in the green channel and v in the blue channel. What does ImageJ say in debug mode when you open the file created by capturing with VirtualDub? (Edit>Options>Misc, 'debug' on) Avoiding any conversion would be the cleanest way to access the original data. --- By the way, the 12bit/pixel video files do not drop bits. Color information is stored only for blocks of 2x2 pixels. This gives you 4 bytes grayscale and 2 bytes color for each block of 4x4 pixels, i.e. 6 bytes for 4 pixels. Michael ________________________________________________________________ On Jun 10, 2013, at 15:44, Seth Pappas wrote: > Greetings, > I am currently using the Quicktime plugin to view live video from a USB camera. > The data coming out of the camera is in YUY2 format....sort of (two bytes per > pixel...but its a 12 bit camera output so we dropped the least 4 bits into the U > byte). Using the Quicktime Capture scheme to view video, the code translates > YUY2 into RGB.... and it is difficult to recover the U term. > Is there a way to view video directly as YUY2? I tried the VirtualDub approach > and IJ did not like it....was not able to open the AVI file. > Even if it did work, you have to view/capture/save the video in VirtualDub first > and then open IJ. I want to do it all in IJ. > > Any insight would be much appreciated. > > Thanks, > > Seth Pappas -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html |
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Michael,
Thanks for the information. I see how the method you described would work...modify the avi reader....but I was trying to avoid having to make an avi file outside of IJ. And since the Quicktime utility runs well: displays the live video and lets me store a still image, I wanted to try to do everything in IJ. In an ideal situation, I could go into the Quicktime plugin and modify it to NOT convert the 8 bit data stream to RGB. Instead, I want it to display the stream as YUY2 and then capture a single frame in the same format...but since QT is a Directshow type of viewer, I am not sure if it is possible (even after reading your email....since I am not opening pre-existing avi files). So the best thing for me would be to saved a single frame of the RGB image from the QT plugin and convert it during the save operation. I see the process as follows after performing steps 1 and 2: 1. Open the live video using file/import/video 2. Press the space bar to capture a single frame. now: 3. Modify the existing save routinewhich would take the RGB and reconvert it into the format it came in as: YUY2. There are several documents that explain how to extract YUY2 data from the RGB info in addition to the example you mentioned, so I would try one of those equations.....I have been able to do it in MATLAB and although I don't think the 12 bit values are exactly what they should be, the final image that is rendered is very good. (might be a good time to mention that I have 0 Java experience...but I am a pretty good code hijacker and was hoping to just find some that I could modify). Regarding the error message for reading the avi filer made by VirtualDub with AVI reader, it says An error occurred.....AVI file must be uncompressed. I would completely understand if you wanted to terminate this email conversation.... Thanks, Seth -----Original Message----- From: Michael Schmid <[hidden email]> To: IMAGEJ <[hidden email]> Sent: Mon, Jun 10, 2013 10:55 am Subject: Re: Viewing YUY2 video in IJ Hi Seth, recent versions of ImageJ can open uncompressed YUV-based avi files with 12 bits/pixels (YV12, I420, NV12, NV21). If it is a different format, use ffmpeg to convert it to an YUY2-type format like NV12: ffmpeg -i infile.avi -pix_fmt nv12 -f avi -vcodec rawvideo outfile.avi To get the the Y and U bytes, you can take the AVI_Reader from the ImageJ source and modify it to get an external plugin (replace 'package ij.plugin;' by 'import ij.plugin.*;'. Then modify writeRGBfromYUV in a suitable way, e.g.: int r=u, g=y, b=v; the resulting image will have the raw u in the red channel, y in the green channel and v in the blue channel. What does ImageJ say in debug mode when you open the file created by capturing with VirtualDub? (Edit>Options>Misc, 'debug' on) Avoiding any conversion would be the cleanest way to access the original data. --- By the way, the 12bit/pixel video files do not drop bits. Color information is stored only for blocks of 2x2 pixels. This gives you 4 bytes grayscale and 2 bytes color for each block of 4x4 pixels, i.e. 6 bytes for 4 pixels. Michael ________________________________________________________________ On Jun 10, 2013, at 15:44, Seth Pappas wrote: > Greetings, > I am currently using the Quicktime plugin to view live video from a USB camera. > The data coming out of the camera is in YUY2 format....sort of (two bytes per > pixel...but its a 12 bit camera output so we dropped the least 4 bits into the U > byte). Using the Quicktime Capture scheme to view video, the code translates > YUY2 into RGB.... and it is difficult to recover the U term. > Is there a way to view video directly as YUY2? I tried the VirtualDub approach > and IJ did not like it....was not able to open the AVI file. > Even if it did work, you have to view/capture/save the video in VirtualDub first > and then open IJ. I want to do it all in IJ. > > Any insight would be much appreciated. > > Thanks, > > Seth Pappas -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html |
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Hi Seth,
if you want to try in the QuickTime_Capture.java plugin, you could have a look at the pixel formats. You might try replacing QDGraphics.kDefaultPixelFormat or k32BGRAPixelFormat by something else like kYVYU422PixelFormat, see the constants in http://quicktimeforjava.zzl.org/quicktime/qd/QDConstants.html But I can't say whether this works. Michael ________________________________________________________________ On Jun 10, 2013, at 18:31, Seth Pappas wrote: > Michael, > Thanks for the information. > I see how the method you described would work...modify the avi reader....but > I was trying to avoid having to make an avi file outside of IJ. And since the Quicktime utility runs well: displays the live video and lets me store a still image, I wanted to try to do everything in IJ. > > In an ideal situation, I could go into the Quicktime plugin and modify it to NOT convert the 8 bit data stream to RGB. Instead, I want it to display the stream as YUY2 and then capture a single frame in the same format...but since QT is a Directshow type of viewer, I am not sure if it is possible (even after reading your email....since I am not opening pre-existing avi files). > > So the best thing for me would be to saved a single frame of the RGB image from the QT plugin and convert it during the save operation. I see the process as follows after performing steps 1 and 2: > > 1. Open the live video using file/import/video > 2. Press the space bar to capture a single frame. > now: > 3. Modify the existing save routinewhich would take the RGB and reconvert it into the format it came in as: YUY2. There are several documents that explain how to extract YUY2 data from the RGB info in addition to the example you mentioned, so I would try one of those equations.....I have been able to do it in MATLAB and although I don't think the 12 bit values are exactly what they should be, the final image that is rendered is very good. > > (might be a good time to mention that I have 0 Java experience...but I am a pretty good code hijacker and was hoping to just find some that I could modify). > > Regarding the error message for reading the avi filer made by VirtualDub with AVI reader, it says An error occurred.....AVI file must be uncompressed. > > I would completely understand if you wanted to terminate this email conversation.... > > Thanks, > Seth > > > > > > > > > -----Original Message----- > From: Michael Schmid <[hidden email]> > To: IMAGEJ <[hidden email]> > Sent: Mon, Jun 10, 2013 10:55 am > Subject: Re: Viewing YUY2 video in IJ > > > Hi Seth, > > recent versions of ImageJ can open uncompressed YUV-based avi files with 12 > bits/pixels (YV12, I420, NV12, NV21). If it is a different format, use ffmpeg to > convert it to an YUY2-type format like NV12: > > ffmpeg -i infile.avi -pix_fmt nv12 -f avi -vcodec rawvideo outfile.avi > > To get the the Y and U bytes, you can take the AVI_Reader from the ImageJ source > and modify it to get an external plugin (replace 'package ij.plugin;' by 'import > ij.plugin.*;'. Then modify writeRGBfromYUV in a suitable way, e.g.: > int r=u, g=y, b=v; > the resulting image will have the raw u in the red channel, y in the green > channel and v in the blue channel. > > What does ImageJ say in debug mode when you open the file created by capturing > with VirtualDub? (Edit>Options>Misc, 'debug' on) > Avoiding any conversion would be the cleanest way to access the original data. > > --- > By the way, the 12bit/pixel video files do not drop bits. Color information is > stored only for blocks of 2x2 pixels. This gives you 4 bytes grayscale and 2 > bytes color for each block of 4x4 pixels, i.e. 6 bytes for 4 pixels. > > Michael > ________________________________________________________________ > On Jun 10, 2013, at 15:44, Seth Pappas wrote: > >> Greetings, >> I am currently using the Quicktime plugin to view live video from a USB > camera. >> The data coming out of the camera is in YUY2 format....sort of (two bytes per >> pixel...but its a 12 bit camera output so we dropped the least 4 bits into the > U >> byte). Using the Quicktime Capture scheme to view video, the code translates >> YUY2 into RGB.... and it is difficult to recover the U term. >> Is there a way to view video directly as YUY2? I tried the VirtualDub approach > >> and IJ did not like it....was not able to open the AVI file. >> Even if it did work, you have to view/capture/save the video in VirtualDub > first >> and then open IJ. I want to do it all in IJ. >> >> Any insight would be much appreciated. >> >> Thanks, >> >> Seth Pappas > > -- > ImageJ mailing list: http://imagej.nih.gov/ij/list.html > > > > -- > ImageJ mailing list: http://imagej.nih.gov/ij/list.html -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html |
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