On Tue, 2012-01-03 at 00:13 -0600, Jeremiah Benham wrote: > On 01/02/2012 05:36 AM, Richard Shann wrote: > > On Sun, 2012-01-01 at 14:41 -0600, Jeremiah Benham wrote: > >> Are we going to have a release before we start this? > > I think we should. Playback should mark release 1.0 I think. > > What housekeeping things are there outstanding before a release > > candidate is created? > > I am getting these warnings on startup. I don't know if you see it or not: > (denemo:8292): Gtk-CRITICAL **: gtk_menu_item_get_submenu: assertion > `GTK_IS_MENU_ITEM (menu_item)' failed > > (denemo:8292): Gtk-CRITICAL **: gtk_container_foreach: assertion > `GTK_IS_CONTAINER (container)' failed > > (denemo:8292): Gtk-CRITICAL **: gtk_menu_item_get_submenu: assertion > `GTK_IS_MENU_ITEM (menu_item)' failed > > (denemo:8292): Gtk-CRITICAL **: gtk_container_foreach: assertion > `GTK_IS_CONTAINER (container)' failed > > (denemo:8292): Gtk-CRITICAL **: gtk_container_foreach: assertion > `GTK_IS_CONTAINER (container)' failed > > (denemo:8292): Gtk-CRITICAL **: gtk_menu_shell_insert: assertion > `GTK_IS_MENU_SHELL (menu_shell)' failed > When you removed the built-in commands you left them in the denemoui.xml menu builder, which seems to have been the source of that.
> > Should we create scheme alternatives to the built-ins for dynamics? Some > of these would require multiple glyphs FFF, ppp, etc... I only see non-built-in dynamics (at Directives->Dynamics) and the built-in cresc etc. If there are others I don't think we need them, though whether having the dynamics as standalone objects is good or not I can't really say (I don't have occasion to use them) > > It is not a big deal but the ornaments and articulations with the > override above always have glyph x number of pixels above the note. > Intead it should somehow be x number of pixels above the top line. This > is true unless note stem is > height of top staff line. The problem with > it now is if someone puts a fermata on a middle c, the fermata would > appear around the 1st or 2nd staff line. hmm, yes I was noticing that myself recently - some things, like staccato need to stay with the notehead, other things not. Needs some more thought, and probably another override (sigh). Richard > > Jeremiah > > > > > Richard > > > > > >> Jeremiah > >> > >> Sent from my Samsung smartphone on AT&T > >> > >> Richard Shann<[email protected]> wrote: > >> > >>> I think the next big step for Denemo will be to get the playback working > >>> in its own thread. > >>> > >>> Below are some ideas for how to do this, first there are some notes > >>> which you can cut out if you already know how the soc code is working. > >>> > >>> 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< > >>> 8>< 8>< 8>< > >>> I have studied the soc branch code and made the following notes: > >>> > >>> The playback works by using two threads, one is the > >>> process_thread_func() of the backend chosen (I see alsabackend.c and > >>> dummybackend.c so far) and the other is the queue_thread_func() in > >>> audiointerface.c > >>> > >>> The process_thread_func() creates a mutex and then runs a loop: > >>> the loop gets the system time g_get_current_time() and to it adds 5ms (a > >>> compiler constant called PLAYBACK_INTERVAL). This time is then used for > >>> a timed wait on a condition with the mutex, that is a call to > >>> g_cond_timed_wait(). This means that the thread waits for the condition > >>> process_cond to be signalled or until the 5ms have elapsed. > >>> The g_cond_timed_wait() unlocks the mutex before the thread sleeps and > >>> locks it when it continues. > >>> ***Question*** is it ok that the mutex has not been locked for the first > >>> time (and correspondingly, at the end g_mutex_free() is called without > >>> unlocking the mutex, is that ok?). > >>> > >>> Next a check is made for quitting the loop - this is done by making an > >>> atomic access to an int which is set by the alsa_seq_destroy() call. > >>> ***Question*** does that need to be an atomic access? The int in > >>> question is just a boolean, so in C it just means that if any of the > >>> bits are set it is true. So it really doesn't matter if another thread > >>> is halfway through setting it. > >>> > >>> Next is code which I think is for MIDI input - I ignore this here. > >>> > >>> Now the playback code continues by getting the current time and > >>> subtracting a value called playback_start_time. This latter value is set > >>> up when starting the playing by getting the system time and subtracting > >>> a value "playback_time" which is kept in audiointerface.c and controlled > >>> by calls to the function update_playback_time() and initialized by > >>> midi_play() to Denemo.gui->si->start_time. This last is the time in > >>> seconds from the start of the piece which the user has set as the time > >>> to start from (e.g. via d-SetPlaybackInterval etc). > >>> So for the case of playing an entire movement, this is zero, and the > >>> playback_start_time is the system time when the play was initiated. > >>> > >>> Back to the loop which the process_thread_func() runs... > >>> > >>> The difference between the current time and the playback_start_time is > >>> called the playback_time and is time in seconds along the midi track > >>> where the next event should be taken from. > >>> > >>> After a check for reset (I ignore that here) an event is read from the > >>> queue. This is the call read_event_from_queue() in audiointerface.c. > >>> This is called with a parameter called until_time which is set to the > >>> playback_time plus 5ms (the PLAYBACK_INTERVAL value again). After > >>> checking for stop play conditions (discuss later) this calls into > >>> eventqueue.c for the function event_queue_read_output(). This checks the > >>> midi event time is< the until_time and returns TRUE and the event if so > >>> otherwise FALSE. > >>> Further events are read until this call to get an event from the queue > >>> fails. > >>> Finally before the loop begins again the playback_time that the backend > >>> has, is "sent back" to audiointerface.c via update_playback_time(). > >>> > >>> 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< 8>< > >>> 8>< 8>< 8>< > >>> > >>> This code lacks the flexibility to speed up, slow down or pause the > >>> playback - once the playback_start_time has been fixed the midi events > >>> following that time will be sent out by referencing the current system > >>> time. > >>> This could be changed so that instead of executing g_get_current_time() > >>> the time is obtained from a thread which manages the requests from the > >>> user to pause, change tempo etc. > >>> > >>> Currently, I think there are two examples of how to do this in Denemo. > >>> The first was the one I wrote to allow live change of tempo - very > >>> useful for getting the right tempo by adjusting the slider while the > >>> music is playing. The second I wrote to allow the playback to follow a > >>> user playing along with it. > >>> Only the first of these is easy enough to understand that I still have > >>> it in my head: when the tempo slider is moved all the elapsed times that > >>> are obtained are scaled. To make this work, the playback_start_time has > >>> to be re-calculated - so it is as if we had been playing since then at > >>> the new tempo and had just reached the current playback time. In this > >>> way we do not have to keep a history of all the tempo changes. > >>> The second method of controlling the playback was for following the > >>> player (or conductor). In this case the user is setting a time at which > >>> the playback should pause (unless the user has updated it meanwhile). > >>> I am not sure if these could be unified. > >>> > >>> What would the new time-control thread look like? Well, for all the > >>> paused time it could add up the total of pauses so far and subtract > >>> these from the time value it returns. While actually in a pause, I guess > >>> it would just keep returning the same time - only when the pause is > >>> ended would it increment the total amount of pause time and subtract > >>> that from the time value it would otherwise return. I guess it could > >>> also manage the tempo change signal, adjusting the playback_start_time > >>> and scaling the times it returns. Perhaps though, it should be returning > >>> not absolute times but times since start? So it would be returning 0 > >>> during a pause and a scaled difference of (g_get_current_time() - > >>> playback_start_time) and the total_pause_time. (?) > >>> > >>> I would welcome comments. > >>> > >>> Richard Shann > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> _______________________________________________ > >>> Denemo-devel mailing list > >>> [email protected] > >>> https://lists.gnu.org/mailman/listinfo/denemo-devel > > > _______________________________________________ Denemo-devel mailing list [email protected] https://lists.gnu.org/mailman/listinfo/denemo-devel
