[Mixxx-devel] absolute position ?
What message should be used to set the absolute position of the virtual needle of a loaded track given an absolute time position, f.ex. 2mins 34secs 567millisecs? I went through all the relevant docs (I think), incl. controls and HID mappings and didn't find a clear solution. I need to match an analog CDJ's time display with Mixxx's via a timecode CD using absolute timestamps (4 tracks x 15min), i.e. time scale between CDJ/Mixxx needs to be 1:1 and clamp, not stretch. F.ex. vinylcontrol_mode is a 3-way switch, one being absolute, but I don't see the set absolute time message. playPosition is scaled over the length of the track loaded in mixxx, which won't match a timecode CD's track. scratch2 affects the absolute speed, hence the relative position. The absolute time position needs to have at least 22-bit resolution so a gentle pitch bend can go through the engine via that cursor position and behave as expected, i.e. if any scaling/compression is applied along the way it wouldn't chop off the lower bits. It's just to control track position. Precision is critical but right now latency isn't. thx, -- p -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] absolute position ?
I'm confused, what are you trying to do? For vinylcontrol absolute mode, we mostly use the pitch value and then nudge the speed up or down if it drifts too far from the reported timecode position. For CDs, if it's more than .1 seconds off then we just seek to that position. I don't really see the point of having 22 bit resolution. owen On Sat, 2013-07-06 at 11:56 +0200, petah wrote: What message should be used to set the absolute position of the virtual needle of a loaded track given an absolute time position, f.ex. 2mins 34secs 567millisecs? I went through all the relevant docs (I think), incl. controls and HID mappings and didn't find a clear solution. I need to match an analog CDJ's time display with Mixxx's via a timecode CD using absolute timestamps (4 tracks x 15min), i.e. time scale between CDJ/Mixxx needs to be 1:1 and clamp, not stretch. F.ex. vinylcontrol_mode is a 3-way switch, one being absolute, but I don't see the set absolute time message. playPosition is scaled over the length of the track loaded in mixxx, which won't match a timecode CD's track. scratch2 affects the absolute speed, hence the relative position. The absolute time position needs to have at least 22-bit resolution so a gentle pitch bend can go through the engine via that cursor position and behave as expected, i.e. if any scaling/compression is applied along the way it wouldn't chop off the lower bits. It's just to control track position. Precision is critical but right now latency isn't. thx, -- p -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] absolute position ?
On Sat, 06 Jul 2013 11:14:13 -0400 Owen Williams owilliams-opwvymzfgylytjvyw6y...@public.gmane.org wrote: I'm confused, what are you trying to do? For vinylcontrol absolute mode, we mostly use the pitch value and then nudge the speed up or down if it drifts too far from the reported timecode position.For CDs, if it's more than .1 seconds off then we just seek to that position. I don't really see the point of having 22 bit resolution. 22-bits is the maximum resolution the CDJ timecode returns for a single-track CD. On a 4-track CD a timestamp is 2.38ms or a worst-case latency of ~5ms. OTOH nudging +/- 0.1 second is 100ms or 20x worse. Dropping seek commands based on acceptable drift is fine on full-resolution incoming timecode at the receiver end, but doing roundtrips and diffs to reach an absolute position makes no sense if the timecode is absolute to begin with. I'd turn the comment around: I don't see the point of truncating bits in the protocol to later try recovering them by chasing the needle :) -- p On Sat, 2013-07-06 at 11:56 +0200, petah wrote: What message should be used to set the absolute position of the virtual needle of a loaded track given an absolute time position, f.ex. 2mins 34secs 567millisecs? I went through all the relevant docs (I think), incl. controls and HID mappings and didn't find a clear solution. I need to match an analog CDJ's time display with Mixxx's via a timecode CD using absolute timestamps (4 tracks x 15min), i.e. time scale between CDJ/Mixxx needs to be 1:1 and clamp, not stretch. F.ex. vinylcontrol_mode is a 3-way switch, one being absolute, but I don't see the set absolute time message. playPosition is scaled over the length of the track loaded in mixxx, which won't match a timecode CD's track. scratch2 affects the absolute speed, hence the relative position. The absolute time position needs to have at least 22-bit resolution so a gentle pitch bend can go through the engine via that cursor position and behave as expected, i.e. if any scaling/compression is applied along the way it wouldn't chop off the lower bits. It's just to control track position. Precision is critical but right now latency isn't. thx, -- p -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] absolute position ?
On Sat, 06 Jul 2013 11:14:13 -0400 Owen Williams owilliams-opwvymzfgylytjvyw6y...@public.gmane.org wrote: I'm confused, what are you trying to do? For vinylcontrol absolute mode, we mostly use the pitch value and then nudge the speed up or down if it drifts too far from the reported timecode position.For CDs, if it's more than .1 seconds off then we just seek to that position. I don't really see the point of having 22 bit resolution. 22-bits is the maximum resolution the CDJ timecode returns for a single-track CD. On a 4-track CD a timestamp is 2.38ms or a worst-case latency of ~5ms. OTOH nudging +/- 0.1 second is 100ms or 20x worse. Dropping seek commands based on acceptable drift is fine on full-resolution incoming timecode at the receiver end, but doing roundtrips and diffs to reach an absolute position makes no sense if the timecode is absolute to begin with. I'd turn the comment around: I don't see the point of truncating bits in the protocol to later try recovering them by chasing the needle :) -- p On Sat, 2013-07-06 at 11:56 +0200, petah wrote: What message should be used to set the absolute position of the virtual needle of a loaded track given an absolute time position, f.ex. 2mins 34secs 567millisecs? I went through all the relevant docs (I think), incl. controls and HID mappings and didn't find a clear solution. I need to match an analog CDJ's time display with Mixxx's via a timecode CD using absolute timestamps (4 tracks x 15min), i.e. time scale between CDJ/Mixxx needs to be 1:1 and clamp, not stretch. F.ex. vinylcontrol_mode is a 3-way switch, one being absolute, but I don't see the set absolute time message. playPosition is scaled over the length of the track loaded in mixxx, which won't match a timecode CD's track. scratch2 affects the absolute speed, hence the relative position. The absolute time position needs to have at least 22-bit resolution so a gentle pitch bend can go through the engine via that cursor position and behave as expected, i.e. if any scaling/compression is applied along the way it wouldn't chop off the lower bits. It's just to control track position. Precision is critical but right now latency isn't. thx, -- p -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] help! how to get data source for supporting geting controller presets from web?
Hi 魏欣 Here some thought. But apologize if they are all rubbish, because I did not follow your work that close. I am not sure if I get your point. It is correct that you are trying to put the xml mapping file logical content in you database? Is the mapping xml file generated from the database later? If so, I am not in favor with this idea, because it will put additional limitations to the Mixxx and Mapping development. It is possible to store the mapping files as they are it is into the database? If not, we Mixxx have a parser for the xml mappings. Did you have a look at it? It stores the data from the xml in structures hand hash tables. Maybe it is a good idea to split this part into a separate so/dll and add your database code to it. This way we can maintain all midi mapping code at one place. Is it possible to use C++ shared obejcts within the backstage server? Hope that helps! Kind regards, Daniel 2013/7/6 魏欣 weixind...@gmail.com Hi, I am working on providing interfaces for geting forum presets from server. Now I have deployed a server on my own computer ,built the database and been able to get database data from mixxx client through Tastypie API. But I find a problem that I have been ignored. It is how and where I can get presets data for filling server database. Now I have an idea that I can write a script parsing xml files in '/res/controllers/', and use these data to fill in server database tables. And for mixxx client, in order to support search from local and web server, we also should build tables at local database for presets. During initialization, Mixxx scans all the files in '/res/controllers/' and exports the presets info data into local database. The process that users search and download presets from web server is just to update local database. But I guess a problem is that exporting data from xml files may be incomplete, and some preset xml file maybe need some changes. Can you give me some suggestions? -- Best Regards! Xin Wei -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] absolute position ?
Like I said, we do playback based on pitch, not position. Is there a problem you're trying to solve? Is there something wrong with how absolute position playback is working? On Sat, 2013-07-06 at 19:08 +0200, petah wrote: On Sat, 06 Jul 2013 11:14:13 -0400 Owen Williams owilliams-opwvymzfgylytjvyw6y...@public.gmane.org wrote: I'm confused, what are you trying to do? For vinylcontrol absolute mode, we mostly use the pitch value and then nudge the speed up or down if it drifts too far from the reported timecode position.For CDs, if it's more than .1 seconds off then we just seek to that position. I don't really see the point of having 22 bit resolution. 22-bits is the maximum resolution the CDJ timecode returns for a single-track CD. On a 4-track CD a timestamp is 2.38ms or a worst-case latency of ~5ms. OTOH nudging +/- 0.1 second is 100ms or 20x worse. Dropping seek commands based on acceptable drift is fine on full-resolution incoming timecode at the receiver end, but doing roundtrips and diffs to reach an absolute position makes no sense if the timecode is absolute to begin with. I'd turn the comment around: I don't see the point of truncating bits in the protocol to later try recovering them by chasing the needle :) -- p On Sat, 2013-07-06 at 11:56 +0200, petah wrote: What message should be used to set the absolute position of the virtual needle of a loaded track given an absolute time position, f.ex. 2mins 34secs 567millisecs? I went through all the relevant docs (I think), incl. controls and HID mappings and didn't find a clear solution. I need to match an analog CDJ's time display with Mixxx's via a timecode CD using absolute timestamps (4 tracks x 15min), i.e. time scale between CDJ/Mixxx needs to be 1:1 and clamp, not stretch. F.ex. vinylcontrol_mode is a 3-way switch, one being absolute, but I don't see the set absolute time message. playPosition is scaled over the length of the track loaded in mixxx, which won't match a timecode CD's track. scratch2 affects the absolute speed, hence the relative position. The absolute time position needs to have at least 22-bit resolution so a gentle pitch bend can go through the engine via that cursor position and behave as expected, i.e. if any scaling/compression is applied along the way it wouldn't chop off the lower bits. It's just to control track position. Precision is critical but right now latency isn't. thx, -- p -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list mixxx-devel-5nwgofrqmnerv+lv9mx5uipxlwaov...@public.gmane.org https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel
Re: [Mixxx-devel] help! how to get data source for supporting geting controller presets from web?
Hi Daniel Thanks a lot! 2013/7/7 Daniel Schürmann dasch...@mixxx.org Hi 魏欣 Here some thought. But apologize if they are all rubbish, because I did not follow your work that close. I am not sure if I get your point. It is correct that you are trying to put the xml mapping file logical content in you database? Yes, I am. Is the mapping xml file generated from the database later? If so, I am not in favor with this idea, because it will put additional limitations to the Mixxx and Mapping development. It is possible to store the mapping files as they are it is into the database? No, I just want to put the xml mapping file logical content in my database, but it is not enough. Another two items, presets certification status and controller cover picture is necessary for me to implement my search function I have designed. I know that it's better not put additional limitations to the Mixxx and Mapping development, So I have an idea that I build another xml file which store preset name(this is same as name in xml mapping file), preset pid, cover pictureand certification status(these three items are necessary for me and going to add into my database. ) of all the preset in /res/controllers. This xml file will be parsed and the content will be pulled into my database at the same time with the xml mapping file logical content pulled into my database. How about this way? In fact I think this way is a bit wierd, presets certification status and controller cover picture shoud be same as scriptfiles stored in xml mapping file in logic. If not, we Mixxx have a parser for the xml mappings. Did you have a look at it? It stores the data from the xml in structures hand hash tables. Maybe it is a good idea to split this part into a separate so/dll and add your database code to it. This way we can maintain all midi mapping code at one place. I have readed the parser code. I have planed to make use of it to pull xml mapping file content into my database. Is it possible to use C++ shared obejcts within the backstage server? I have written a parser script in Python within the backstage server. Is it necessary to use C++? This script file will be run only when we deploy our backstage server. Hope that helps! Thanks again! Kind regards, Daniel Here I give a list of columns of preset table and file storage table in my planed client database. preset table 1) pid.(uuid. this should stay the same with server side database) 2) author. 3) url. Its values may be null for preset build by mixxx, a forums link for preset coming from mixxx forum, and a wiki link for preset coming from mixxx wiki. 4) description. 5) preset_source. If xml mapping preset file include forums, its value is forums and if include wiki, its value is wiki, otherwise its value is mixxx. 6) preset_status. Its values are certificated,uncertificated, and certificating. 7) mixxx_version 8) preset_name 9) controller_name 10) schema_version file storage table 1) fid(auto increment) 2) pid(Foreign key) 3) file type. its value are xml,js,png(show covers for search results) 4) file name 5) directory The contents in red are what I can not get from our current xml mapping preset file. Best Regards, weixin 2013/7/6 魏欣 weixind...@gmail.com Hi, I am working on providing interfaces for geting forum presets from server. Now I have deployed a server on my own computer ,built the database and been able to get database data from mixxx client through Tastypie API. But I find a problem that I have been ignored. It is how and where I can get presets data for filling server database. Now I have an idea that I can write a script parsing xml files in '/res/controllers/', and use these data to fill in server database tables. And for mixxx client, in order to support search from local and web server, we also should build tables at local database for presets. During initialization, Mixxx scans all the files in '/res/controllers/' and exports the presets info data into local database. The process that users search and download presets from web server is just to update local database. But I guess a problem is that exporting data from xml files may be incomplete, and some preset xml file maybe need some changes. Can you give me some suggestions? -- Best Regards! Xin Wei -- This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev ___ Get Mixxx, the #1 Free MP3 DJ Mixing software Today http://mixxx.org Mixxx-devel mailing list Mixxx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mixxx-devel -- This SF.net email is sponsored by Windows: Build for Windows Store.
