[libbluray-devel] first patch-set

[Erik Van Grunderbeeck]

>HDMV and BD-J applications use the registers too. Initial values are
>fixed and all players use the same initial values. Changing those may
>cause problems in HDMV / BD-J applications, so filtering should be
>based on some flag instead of changing initial values.

I did that initially, but it got over complicated (since I also needed to
restore flags, and backup them, ..)


>Following applies only to navigation mode started with bd_play() -
>that's also the only scenario where restore is currently used:

>When title is 0xffff other values (playlist, clip, chapter, angle,
>current time, ...) have no meaning and should not be used at all. But
>application should still cache the values for later use: when title
>playback starts, only changed values are signaled to application.

Thats what the patch does: the values that are changed/restored are stored,
but not send to the player when they are the initialize values from startup
(so that only when we have real valid values are available, they are send).
Note that the change I made doesnt change anything internally on flow. It
just doesnt send back to the user.

Question: does the spec state that playlist and playlist item should be
initailized to 0?

>Maybe we could drop all status events in _process_psr_event() when
>title is 0xffff ? Well, then, some care should be taken to ensure
>events are always sent before playback starts.

Might be a possibility too. Do you mean check PSR4 for 0xffff and dont send
if thats the case?

>One possible solution is to block all status events while HDMV VM is
>running and generate events when HDMV VM enters suspended state
> (playlist playback starts and register values are valid).
>bd_read_ext() won't return any data before that as playback is
>suspended while HDMV VM is running,
>Here it might be good idea to run the whole HDMV application once
>without returning to application for every event. HDMV execution is
>supposed to be instant i.e. take no time. Not returning from
>bd_read_ext() should prevent application from doing anything stupid
>like seeking or changing title :)

Which was my problem with playlist value 0 ;)

>> 2) I saw some issues where on playback on object gets restored (ege play
>> title, then go back if I remember correctly). The restore object thus
>> resends the init values of the registers again, and then whatever the
>> statemachine is giving. Ill try to repro the restore scenario if you
want.

>No need, I can see it too and agree it may cause problems and is
>misleading (BD_EVENT_PLAYLIST 0 when playlist 0 is not playing -->
>application does something, maybe tries to fetch title info for
>possibly unexisting playlist 0).

Yep.

>> Ill check with the BR I have that shows the problem. If you want, and let
me
>> know how I can check for the muxing I can probably give you a patch (I
know
>> and have experience on mpegts muxing)

>Demuxing is already implemented, you just need to hook it to bd_read()
>when there is active/selected IG stream in the main path. I don't have
>such samples so I didn't add it yet. _find_ig_stream() should always
>find current IG stream. If it is muxed to main path, sub_path_idx is
>not set. In that case we need some flag to tell when embedded IG
>stream should be demuxed, and call gc_decode_ts(,...,ig_pid,...) for
>every block. Maybe just add IG stream pid field to BD_STREAM and call
>gc_decode_ts() in _read_block if PID is set ?

Need to make sure the pts values are set correctly in the controller also.
Apps that are cached reading ahead of the stream will be out of sync
otherwise. I'll look into it.

>_find_ig_stream() needs to be called at least when opening playlist
>and when when PSR for active IG stream changes. Currently it is not
>called if there are no sub-paths. Current code also doesn't support
>changing IG stream in middle of playlist, so that could be added too
>:).

>Maybe we need to reset graphics controller after some operations (seek ?).
Is seek allowed when an IG stream is running?

>Synchronous menus can be valid only during certain perioid of clip, so
>some logic should be implemented in graphics controller too. Maybe we
>need to run it periodically so that possibly visible menu is
>invalidated when it is not anymore valid (based on current player SCR
>and composition_timeout_pts). Also selection_timeout_pts handling is
>not implemented yet...

I think in general some callback/hook is needed that will run the VM machine
for HDMV without doing an actuall read for movie data (as in; update the
animation/page).

> Further remarks ;)
>
>> 1) Theres a subtle bug if you use the FILTER values (ege
>> TITLES_FILTER_DUP_TITLE/TITLES_FILTER_DUP_CLIP). If that is used then
some
>> valid mpls's will be filtered that are valid when the BR is played in
>> navigation mode. The list that navigation mode uses should be the full
list
>> available on the disc, while the filter values should return a filter
lists
>> based on that. I am also not really sure why that filtering is there
anyway?

>Yes, bd_get_titles() and bd_select_title() are quite useless in
>navigation mode (using bd_select_title() may even cause some problems
>...). Maybe bd_play() should always populate complete title list and
>even disable further calls to bd_get_titles().
>Filtering is intended for direct playlist playback when menus are not
>used at all. The idea is to filter menu backgrounds etc. from title
>list.

That, or always read the complete list, and return a duplicate list (that
the user needs to free explicitly) when he/she does a filtered retrieve.

>I assume you're referring to animations in buttons (controlled by
>start_object_id_ref, end_object_id_ref and repeat_flag) and in menu
>pages (in/out effects) ?

>HDMV VM can run only when playlist is not playing. It is suspended
>until playback stops. Animations should be implemented in graphics
>controller.

Let me explain better, or try to ;). I have some BR's that have LPCM data in
really small chunks embeded in the stream (960 bytes) every 20 milliseconds
or so. A result of this is that you need to buffer a good chunk of audio
(2-3 seconds) before you can start feeding the audio playback device.
Playing these small lpcm chunks as they arrive leads the cracking sounds
(the audio device runs out of audio to play to soon because of the small
chunks). I thus need to buffer a couple of seconds of the total movie (this
also helps greatly on slower machines that have no hardware or multicore
decoding for video). This however means that when a playlist/playitem
changes, I need to wait until that buffer runs clear. I thus can not call
bd_read_ext() anymore, since that would continue to retrieve movie data for
a playlist I am not at yet. However, I still need valid user feedback for
menu's (the user moves the mouse over menu's, and they dynamically show
different size, highlight,  etc). Basically, the VM needs to run for any new
instructions set on user input IF its just an animation. The VM however only
runs on bd_read_ext()....

Right now I changed bd_read_ext(), passing the title_idx I am playing. When
that title_idx matches the one that libbluray has, it runs the VM based on
the program that was set. When there is no program, or it does not match, it
returns. 

>You can use bd_user_input(..., BD_VK_NONE) to trigger page rendering.
Yes, but that only sets new vm instructions. Does do not run until a new
read().

>Maybe BD_VK_NONE should be mapped to GC_CTRL_NOP to always force page
>rendering (currently it does nothing if menu is already visible). This
>code path already supports setting PSR_TIME; it should be used for
>animation timing. Adding button animations should be quite simple
>using this method, I already have some code for that but it is far
>from complete :)
Except that the BR that I have doesnt seem to set/use the PSR time
register/instruction. I saw that piece of code after I send my last email,
and checked. It does set the tickcount variable in its bog button.

I'll look into the muxing part and see if I can figure it out. Btw; if you
need any of the parts of the disks that show behavior, let me know.

Erik
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