Re: [osg-users] Streaming of high resolution images
Hi Francesco, Quoting "Francesco Argese" : Yes, I load a certain number of images (a lot of images, for example 20.000 at 1400x1050 resolution-jpg or tga) with readImageFile at the initialization of the application and I load them in memory (inside std::vector) at startup. To visualize all the images in a smoothing way (like a movie) with play, forward, rewind, skipToNextFrame, skipToPreviousFrame command I iterate the array elements. My problem is that I can load inside the vector a little number of images (about one hundred). Then I have not enough memory error. I suppose that this error is normal because I load all the uncompressed images in memory (also with .jpg) and I'm looking for a method to solve this problem. I have already tried to destroy old images but in that case there is the following problem: the process of loading images from my hard disk to ram require about two times the time required for visualization at 30 fps so it arrives a moment where the buffer is full. As regards ramdisk probably it could be a solution (implementing parallel threads) but on Windows it has portability problems due to You have two problems: 1) limited RAM and address space, which means you cannot load all the frames at once. To solve this you need a way to only keep the frames you currently need in RAM and free them when they're no longer needed. For example keep N frames ahead and N behind your current play position. When you move the play position you can free some frames and load others. however, you have another problem: 2) limited disk I/O bandwidth If your I/O bandwidth can't supply the frames at least as fast as you're playing them back you're simply out of luck. You didn't mention how big the individual frames are but an uncompressed 1440x1050 8-bit RGB frame needs a little over 4.3 MB. At a playback rate of 30 fps that's over 129 MB/s!!! Let's say you have jpeg compression of 50% then it's still way 60 MB/s. If you can set aside a ramdisk to hold all your frames you would be fine but for 20,000 frames I don't that's an option. (It would make your RAM vendor very happy though! :-) The only solution I see is to use a compressed file format instead, like avi/mp4/h.264. Sorry. /ulrich ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi Art, Quoting "Art Tevs" : Why would you read from disk into a RAM disk, then read from RAM disk into, err, RAM again? Instead of reading straight from disk into your RAM cache? ... you mentioned exactly the same what I told by using RAM-disk and external application which will load the data into it. So, you agree that this is the way to go ;) ? In general yes, but I don't see any benefit in reading frame of disk into a RAM disk in one thread and then reading them *again* from RAM disk into process memory in another thread (and then upload them to texture memory). Cheers, /ulrich ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi Francesco, Quoting "Francesco Argese" : Still: the resolution you mentioned (1440x1050) requires ~108 MB/s for 8-bit RGB @ 25 fps (and over 140 MB/s for 10-bit or RGBA). You need a few drives to do that... What do you mean with "You need a few drives to do that..."? That the majority of hard drives support a flow like that? No, in the absolutely best case (start of the disk, no other I/O; basically a theoretical max) you get maybe 50 MB/s tops from a single desktop drive. To get any more you need to use more disks and stripe them. /ulrich ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi, maybe you can exercise the new ffmpeg plugin that Robert just comitted :) Take your images and stick them into an avi file with mencoder, e.g.: mencoder mf://*.jpg -ovc lavc -lavcopts vcodec=ljpeg:keyint=1 -mf fps=30 -o mynewavi.avi you can select other codec if you want. If you can tolerate compression, try mjpeg instead of lossless (ljpeg). You will have to balance disk speed vs uncompress time on cpu. If the ffmpeg plugin or ffplay or mplayer can play your avi at 30fps then at least you know your hardware can handle the rate. Playing in reverse at full rate might be more difficult. Not sure if the plugin supports single frame step either. jp Francesco Argese wrote: J.P. Delport wrote: Hi, are you creating a new image every time using osgDB::readImageFile? If so, then you might be just plain running out of memory if you are not destroying old images. Yes, I load a certain number of images (a lot of images, for example 20.000 at 1400x1050 resolution-jpg or tga) with readImageFile at the initialization of the application and I load them in memory (inside std::vector) at startup. To visualize all the images in a smoothing way (like a movie) with play, forward, rewind, skipToNextFrame, skipToPreviousFrame command I iterate the array elements. My problem is that I can load inside the vector a little number of images (about one hundred). Then I have not enough memory error. I suppose that this error is normal because I load all the uncompressed images in memory (also with .jpg) and I'm looking for a method to solve this problem. I have already tried to destroy old images but in that case there is the following problem: the process of loading images from my hard disk to ram require about two times the time required for visualization at 30 fps so it arrives a moment where the buffer is full. As regards ramdisk probably it could be a solution (implementing parallel threads) but on Windows it has portability problems due to the installation of a driver that probably I cannot install on target PC of my application. Thanks all for the useful answers (you are giving me new roads to follow) Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7514#7514 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. The full disclaimer details can be found at http://www.csir.co.za/disclaimer.html. This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks Transtec Computers for their support. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
J.P. Delport wrote: > Hi, > > are you creating a new image every time using osgDB::readImageFile? If > so, then you might be just plain running out of memory if you are not > destroying old images. > Yes, I load a certain number of images (a lot of images, for example 20.000 at 1400x1050 resolution-jpg or tga) with readImageFile at the initialization of the application and I load them in memory (inside std::vector) at startup. To visualize all the images in a smoothing way (like a movie) with play, forward, rewind, skipToNextFrame, skipToPreviousFrame command I iterate the array elements. My problem is that I can load inside the vector a little number of images (about one hundred). Then I have not enough memory error. I suppose that this error is normal because I load all the uncompressed images in memory (also with .jpg) and I'm looking for a method to solve this problem. I have already tried to destroy old images but in that case there is the following problem: the process of loading images from my hard disk to ram require about two times the time required for visualization at 30 fps so it arrives a moment where the buffer is full. As regards ramdisk probably it could be a solution (implementing parallel threads) but on Windows it has portability problems due to the installation of a driver that probably I cannot install on target PC of my application. Thanks all for the useful answers (you are giving me new roads to follow) Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7514#7514 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi Ulrich, Ulrich Hertlein wrote: > > Why would you read from disk into a RAM disk, then read from RAM disk into, > err, RAM > again? Instead of reading straight from disk into your RAM cache? > > ... > > Set up a read thread that reads the images into RAM buffers and upload the > images from the > buffers as needed. At least that way you have the I/O wait in another thread > and not your > draw thread. > you mentioned exactly the same what I told by using RAM-disk and external application which will load the data into it. So, you agree that this is the way to go ;) ? But nevertheless, as soon as coping the data from RAM into VRAM is faster than loading from HDD into RAM, you will always stuck after some time. It doesn't matter how much data you deliver into the RAM buffers from the HDD. After some time you will just reach the end of the buffered data and hence your draw thread will have to wait. Maybe you could try out to stream from HDD to RAM compressed files and uncompress them on the CPU (some simple runtime length encoding or so). Hence 3 threads, streaming, uncompressing and drawing threads. Each of them is working on some kind of RAM buffer. cheers -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7467#7467 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi, are you creating a new image every time using osgDB::readImageFile? If so, then you might be just plain running out of memory if you are not destroying old images. You can destroy the images manually or also search setUnRefImageDataAfterApply in texture classes. I'm not sure how one reads data into the same image with osgDB::readImageFile. jp Francesco Argese wrote: The bottleneck is still your disk I/O bandwidth and if that isn't fast enough you're still out of luck. Yes, the bottleneck is certainly I/O bandwidth: in fact the application doesn't block until It work totally in ram. When RAM is full the paging file (on the hard disk) begin to grow and the application go slow and crush. Still: the resolution you mentioned (1440x1050) requires ~108 MB/s for 8-bit RGB @ 25 fps (and over 140 MB/s for 10-bit or RGBA). You need a few drives to do that... What do you mean with "You need a few drives to do that..."? That the majority of hard drives support a flow like that? I think so but probably the problem could be the loading process of images and I hope that it could be resolved using other techniques (probably customizing implementation of osgDB::readImageFile? probably with ramdisk?). Is it possible or am i wrong? What is the path (in terms of memory) that images follow before to be displayed at video? At the moment i'm already trying using quicktime (inserting images in a .mov) while, as regards ive, there could it be a problem of size because i have a lot of images to display. Thanks all for the useful answers Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7461#7461 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. The full disclaimer details can be found at http://www.csir.co.za/disclaimer.html. This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks Transtec Computers for their support. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
> The bottleneck is still your disk I/O bandwidth and if that isn't fast enough > you're still > out of luck. Yes, the bottleneck is certainly I/O bandwidth: in fact the application doesn't block until It work totally in ram. When RAM is full the paging file (on the hard disk) begin to grow and the application go slow and crush. > Still: the resolution you mentioned (1440x1050) requires ~108 MB/s for 8-bit > RGB @ 25 fps > (and over 140 MB/s for 10-bit or RGBA). You need a few drives to do that... What do you mean with "You need a few drives to do that..."? That the majority of hard drives support a flow like that? I think so but probably the problem could be the loading process of images and I hope that it could be resolved using other techniques (probably customizing implementation of osgDB::readImageFile? probably with ramdisk?). Is it possible or am i wrong? What is the path (in terms of memory) that images follow before to be displayed at video? At the moment i'm already trying using quicktime (inserting images in a .mov) while, as regards ive, there could it be a problem of size because i have a lot of images to display. Thanks all for the useful answers Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7461#7461 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
On 25/2/09 1:35 AM, Art Tevs wrote: you can even stream from a RAM disk, which will increase the performance as well. An external application could stream from the hdd to the ram disk in parallel to your application. For a multicore cpu this shouldn't be a big problem. So you will use the Why would you read from disk into a RAM disk, then read from RAM disk into, err, RAM again? Instead of reading straight from disk into your RAM cache? The bottleneck is still your disk I/O bandwidth and if that isn't fast enough you're still out of luck. Set up a read thread that reads the images into RAM buffers and upload the images from the buffers as needed. At least that way you have the I/O wait in another thread and not your draw thread. Still: the resolution you mentioned (1440x1050) requires ~108 MB/s for 8-bit RGB @ 25 fps (and over 140 MB/s for 10-bit or RGBA). You need a few drives to do that... Cheers, /ulrich ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi all, you can even stream from a RAM disk, which will increase the performance as well. An external application could stream from the hdd to the ram disk in parallel to your application. For a multicore cpu this shouldn't be a big problem. So you will use the ram disk as a cache for your data. I've used similar technique couple of times already in Linux. However, I have no idea how to do so in windows. cheers, art -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7306#7306 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Francesco Argese wrote: > Hi all, > > I'm trying to stream high resolution images in real-time. My problem is that > performance degenerate after some time; this is due to the complete > occupation of the ram and to the slow process of loading an image in memory > that is slower than the visualization frequency needed by my application. > > In which classes is this process handled? Is there a manner to avoid (or to > mitigate) this problem using a different approach? > > I remember that i have already seen this same argument in mailing list but, > doing a search, I have not found what I'm searching for. > It is faster to use texture compression and save the compressed textures as .ive files, then load those. This requires either a preprocessing step to compress the textures or a caching mechanism to use compressed textures once they've been generated. I use the second technique in my application with pretty good results. -Eric ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
> How are you streaming these images? What resolution and format are they? > > When you're talking about streaming I suppose you're using some kind of > compression? I'm not using any form of compression at this moment: I have a set of .tga image at a resolution of 1440x1050 and I have tried to read them both with osgDB::readImageFile function (loading the images at the initialization of application) and using osgimagesequence example. > On > Linux this would most likely be handled by the xine plugin, on OS X possibly > the quicktime > plugin. I have read something about this but i have not understood if both quicktime or xine introduce some form of compression. Thanks Hi Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7288#7288 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Streaming of high resolution images
Hi Francesco, On 24/2/09 8:48 PM, Francesco Argese wrote: I'm trying to stream high resolution images in real-time. My problem is that > performance degenerate after some time; this is due to the complete occupation of the > ram and to the slow process of loading an image in memory that is slower than the > visualization frequency needed by my application. How are you streaming these images? What resolution and format are they? When you're talking about streaming I suppose you're using some kind of compression? On Linux this would most likely be handled by the xine plugin, on OS X possibly the quicktime plugin. They streaming mode determines where to look for a problem. Cheers, /ulrich ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Streaming of high resolution images
Hi all, I'm trying to stream high resolution images in real-time. My problem is that performance degenerate after some time; this is due to the complete occupation of the ram and to the slow process of loading an image in memory that is slower than the visualization frequency needed by my application. In which classes is this process handled? Is there a manner to avoid (or to mitigate) this problem using a different approach? I remember that i have already seen this same argument in mailing list but, doing a search, I have not found what I'm searching for. Thanks in advance Francesco Argese -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=7280#7280 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
