Re: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC
Hi! Sorry for the late reply, but I had no internet for 3 days. Lars: The problem is that the Data API in blender doesn't have such mutexes and as such isn't thread safe, I guess making blender thread safe in this way, requires a GSoC project or even more on its own. Knapp: This is not about interpolation ;-) And why it's not readable? Imagine a thread accesses a pointer while another thread deletes that memory?! Brett: This doesn't change anything regarding the data access. Sergey: Well yes, the question is whether the main thread can do such a preprocessing. At least the cache can be updated with the current frame value once it's reached so that the value is correct at least the second time you playback after a change (not doing changes between first and second playback for sure). Regards ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
Re: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC
Maybe this is an option; having the audio playback as the main time keeper, and then dropping frames in the view-port if they fail to render within time (within frame accuracy). But one problem is for a heavy scene this could mean that no frames are ever rendered in time and all are dropped, a work around could be: measure the average delay it takes to render a frame and skip ahead to rendering the next frame by that delay. -brett --- On Sun, 7/17/11, Martin Poirier the...@yahoo.com wrote: From: Martin Poirier the...@yahoo.com Subject: Re: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC To: bf-blender developers bf-committers@blender.org Date: Sunday, 17 July, 2011, 2:37 PM Hi, I'd like to ask people with good knowledge of Blender's animation and animation related structures to please consider this problem, this is rather important for neXyon's GSOC project. Thanks, Martin --- On Sun, 7/17/11, neXyon nex...@gmail.com wrote: From: neXyon nex...@gmail.com Subject: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC To: bf-committers@blender.org Received: Sunday, July 17, 2011, 2:31 AM Hi guys! There's a serious problem with the way how animation works in regard to audio. The main problem is, that the animation system pushes the output, so it sets the data, renders a frame, advances to next frame (setting the data there) and renders again and so on, this works pretty good for video. But it doesn't work with audio, especially as audio has a very high temporal resolution (48000 eg. samples per second) compared to video (eg 25 frames per second) and moreover for audio the output device pulls the data, instead of the animation system pushing it, so the other way round. I talked to Martin (Poirier) and Joshua (Leung) and even we three together cannot think up a nice solution for the problem, maybe some genious mind here on the list who is more into the animation code than I am has a really nice idea. Here are specific problems in detail: * Subsample Accuracy: To avoid stair steps as we currently have in volume animation. * Multi Threading: Audio runs in a separate thread. * Speed: The access mechanism has to be realtime capable! * Asynchronous access: Audio playback is ahead of video playback normally (buffering the samples, feeding them to the output device). The first point can be solved easily with a proper interpolation if you have two nearby samples, one in the past, one in the future, so this basically requires the animation data to be cached/buffered somehow or at least asynchronous accessible. As the cached data also solves points 3 and 4 it's pretty obvious that we need the data cached, we had that conclusion already. Questionable is now how to get the cache? One obvious solution is to require the user to bake it, but this heavily impacts how easy the system can be used and as we also already concluded this is a really ugly solution. Better is the automatic caching which leads us to the problem point 2 multi threading. I don't know if it's possible to cache in the main thread? I bet not. And as long as blenders (animation) data isn't accessible multithreaded we still have no solution for the problem. So now your help is needed. Any ideas? If not I'll have to do the baking solution to finish the project. Regards ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
[Bf-committers] Help needed! Animation problems for 3D Audio GSoC
Hi, just general consideration taking into account your problems, it looks like making another pass (maybe even few steps ) for animation system with step ahead would resolve the problem. so the animation system will work as is, just there will be another animation system pass with new ( ahead ) time (as if it is a new frame,or maybe even several frames, and all ahead in time ) which will not change anything - just make step forward and save it as a data which can be pushed to audio subsystem (which, can, then, at given current time just interpolate several future and previous points - linear interpolation for positions and quaternion interpolation for rotations between future and past frame ). as for implementation details - it really require someone who knows how animation system works to add there flag to step into future and also output this data. Regards Sergey ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
[Bf-committers] Help needed! Animation problems for 3D Audio GSoC
Hi guys! There's a serious problem with the way how animation works in regard to audio. The main problem is, that the animation system pushes the output, so it sets the data, renders a frame, advances to next frame (setting the data there) and renders again and so on, this works pretty good for video. But it doesn't work with audio, especially as audio has a very high temporal resolution (48000 eg. samples per second) compared to video (eg 25 frames per second) and moreover for audio the output device pulls the data, instead of the animation system pushing it, so the other way round. I talked to Martin (Poirier) and Joshua (Leung) and even we three together cannot think up a nice solution for the problem, maybe some genious mind here on the list who is more into the animation code than I am has a really nice idea. Here are specific problems in detail: * Subsample Accuracy: To avoid stair steps as we currently have in volume animation. * Multi Threading: Audio runs in a separate thread. * Speed: The access mechanism has to be realtime capable! * Asynchronous access: Audio playback is ahead of video playback normally (buffering the samples, feeding them to the output device). The first point can be solved easily with a proper interpolation if you have two nearby samples, one in the past, one in the future, so this basically requires the animation data to be cached/buffered somehow or at least asynchronous accessible. As the cached data also solves points 3 and 4 it's pretty obvious that we need the data cached, we had that conclusion already. Questionable is now how to get the cache? One obvious solution is to require the user to bake it, but this heavily impacts how easy the system can be used and as we also already concluded this is a really ugly solution. Better is the automatic caching which leads us to the problem point 2 multi threading. I don't know if it's possible to cache in the main thread? I bet not. And as long as blenders (animation) data isn't accessible multithreaded we still have no solution for the problem. So now your help is needed. Any ideas? If not I'll have to do the baking solution to finish the project. Regards ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
Re: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC
On Sun, Jul 17, 2011 at 8:31 AM, neXyon nex...@gmail.com wrote: Hi guys! There's a serious problem with the way how animation works in regard to audio. The main problem is, that the animation system pushes the output, so it sets the data, renders a frame, advances to next frame (setting the data there) and renders again and so on, this works pretty good for video. But it doesn't work with audio, especially as audio has a very high temporal resolution (48000 eg. samples per second) compared to video (eg 25 frames per second) and moreover for audio the output device pulls the data, instead of the animation system pushing it, so the other way round. I talked to Martin (Poirier) and Joshua (Leung) and even we three together cannot think up a nice solution for the problem, maybe some genious mind here on the list who is more into the animation code than I am has a really nice idea. Here are specific problems in detail: * Subsample Accuracy: To avoid stair steps as we currently have in volume animation. Use bezier curves to plot the sound volume but I guess you have that bit figured out having just read farther. Why is the animation data not readable multithreaded? I could understand writable though. -- Douglas E Knapp Creative Commons Film Group, Helping people make open source movies with open source software! http://douglas.bespin.org/CommonsFilmGroup/phpBB3/index.php Massage in Gelsenkirchen-Buer: http://douglas.bespin.org/tcm/ztab1.htm Please link to me and trade links with me! Open Source Sci-Fi mmoRPG Game project. http://sf-journey-creations.wikispot.org/Front_Page http://code.google.com/p/perspectiveproject/ ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
Re: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC
Hi, I'd like to ask people with good knowledge of Blender's animation and animation related structures to please consider this problem, this is rather important for neXyon's GSOC project. Thanks, Martin --- On Sun, 7/17/11, neXyon nex...@gmail.com wrote: From: neXyon nex...@gmail.com Subject: [Bf-committers] Help needed! Animation problems for 3D Audio GSoC To: bf-committers@blender.org Received: Sunday, July 17, 2011, 2:31 AM Hi guys! There's a serious problem with the way how animation works in regard to audio. The main problem is, that the animation system pushes the output, so it sets the data, renders a frame, advances to next frame (setting the data there) and renders again and so on, this works pretty good for video. But it doesn't work with audio, especially as audio has a very high temporal resolution (48000 eg. samples per second) compared to video (eg 25 frames per second) and moreover for audio the output device pulls the data, instead of the animation system pushing it, so the other way round. I talked to Martin (Poirier) and Joshua (Leung) and even we three together cannot think up a nice solution for the problem, maybe some genious mind here on the list who is more into the animation code than I am has a really nice idea. Here are specific problems in detail: * Subsample Accuracy: To avoid stair steps as we currently have in volume animation. * Multi Threading: Audio runs in a separate thread. * Speed: The access mechanism has to be realtime capable! * Asynchronous access: Audio playback is ahead of video playback normally (buffering the samples, feeding them to the output device). The first point can be solved easily with a proper interpolation if you have two nearby samples, one in the past, one in the future, so this basically requires the animation data to be cached/buffered somehow or at least asynchronous accessible. As the cached data also solves points 3 and 4 it's pretty obvious that we need the data cached, we had that conclusion already. Questionable is now how to get the cache? One obvious solution is to require the user to bake it, but this heavily impacts how easy the system can be used and as we also already concluded this is a really ugly solution. Better is the automatic caching which leads us to the problem point 2 multi threading. I don't know if it's possible to cache in the main thread? I bet not. And as long as blenders (animation) data isn't accessible multithreaded we still have no solution for the problem. So now your help is needed. Any ideas? If not I'll have to do the baking solution to finish the project. Regards ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers ___ Bf-committers mailing list Bf-committers@blender.org http://lists.blender.org/mailman/listinfo/bf-committers
