Vitor Sessak a écrit :
> On 07/13/2010 09:49 PM, Sebastian Vater wrote:
>>
>
> Is it the list of the rows in chronological order? Is it the list of
> notes in alphabetical order? Also, if I understand well, it is an
> array of linked lists. Why?
Because the user can insert new rows, delete old ones, rearrange them
when editing.
>
>>>> /** Number of order list data used for this channel. */
>>>> uint16_t orders;
>>>>
>>>> /** Number of order list data entries to use for this
>>>> channel. */
>>>> uint16_t length;
>>>>
>>>> /** Repeat start order list data number for this channel. */
>>>> uint16_t rep_start;
>>>>
>>>> /** Volume level for this channel (defaults to 255). */
>>>> uint8_t volume;
>>>> #define AVSEQ_ORDER_LIST_VOLUME 255
>>>>
>>>> /** Sub-volume level for this channel. This is basically channel
>>>> volume divided by 256, but the sub-volume doesn't account
>>>> into actual mixer output (defaults 0). */
>>>> uint8_t sub_volume;
>>>> #define AVSEQ_ORDER_LIST_SUB_VOLUME 0
>>>>
>>>> /** Stereo track panning level for this channel (defaults to
>>>> -128 = central stereo track panning). */
>>>> int8_t track_panning;
>>>> #define AVSEQ_ORDER_LIST_TRACK_PAN -128
>>>>
>>>> /** Stereo track sub-panning level for this channel. This is
>>>> basically track panning divided by 256, but the sub-panning
>>>> doesn't account into actual mixer output (defaults 0). */
>>>> uint8_t track_sub_panning;
>>>> #define AVSEQ_ORDER_LIST_TRACK_SUB_PAN -128
>>>>
>>>> /** Stereo panning level for this channel (defaults to
>>>> -128 = central stereo panning). */
>>>> int8_t channel_panning;
>>>> #define AVSEQ_ORDER_LIST_PANNING -128
>>>>
>>>> /** Stereo sub-panning level for this channel. This is
>>>> basically channel panning divided by 256, but the sub-panning
>>>> doesn't account into actual mixer output (defaults 0). */
>>>> uint8_t channel_sub_panning;
>>>> #define AVSEQ_ORDER_LIST_SUB_PANNING 0
>>>
>>>> /** Compatibility flags for playback. There are rare cases
>>>> where order handling can not be mapped into internal
>>>> playback engine and have to be handled specially. For
>>>> each order list which needs this, this will define new
>>>> flags which tag the player to handle it to that special
>>>> way. */
>>>> uint8_t compat_flags;
>>>
>>> I suppose this is not unused ATM?
>>
>> Fixed.
>>
>>>
>>>> /** Order list playback flags. Some sequencers feature
>>>> surround panning or allow initial muting. which has to
>>>> be taken care specially in the internal playback engine.
>>>> Also sequencers differ in how they handle slides. */
>>>> uint8_t flags;
>>>> #define AVSEQ_ORDER_LIST_FLAG_CHANNEL_SURROUND 0x01 ///< Initial
>>>> channel surround instead of stereo panning
>>>> #define AVSEQ_ORDER_LIST_FLAG_TRACK_SURROUND 0x02 ///< Initial
>>>> track surround instead of stereo panning
>>>> #define AVSEQ_ORDER_LIST_FLAG_MUTED 0x04 ///< Initial
>>>> muted channel
>>>>
>>>> } AVSequencerOrderList;
>>>>
>>>> /**
>>>> * Song order list data structure, this contains actual order list
>>>> data.
>>>> * New fields can be added to the end with minor version bumps.
>>>> * Removal, reordering and changes to existing fields require a major
>>>> * version bump.
>>>> */
>>>> typedef struct AVSequencerOrderData {
>>>> /** AVSequencerTrack pointer to track which should be played. */
>>>> AVSequencerTrack *track;
>>>
>>>> /** Next order list data pointer if seeking forward one
>>>> frame. */
>>>> AVSequencerOrderData *next_pos;
>>>>
>>>> /** Previous order list data pointer if seeking backward one
>>>> frame. */
>>>> AVSequencerOrderData *prev_pos;
>>>
>>> These do not look to belong to the BSS.
>>
>> They are used to allow the composer to define alternative order
>> sequences in case of forward and backward seeking. These alternatives
>> can pre-initialize note data in that case. This is a very rarely used
>> feature, but avoids the problem that instruments are missing if you skip
>> one channel.
>>
>> Example:
>> We have a track playing a new instrument at row 60. If the user skips
>> this track before arriving row 60, it will not be played at all, thus
>> causing silence. Now consider the normal next row, would change data
>> here or even has a complete empty row (but expecting to play a long
>> looped instrument), in that case it would confuse the actual output.
>> These pointers allow the composer to initialize that in case.
>
> Is this about an human user seeking the file he is playing or a
> tracker formats that specify seeking commands?
The composer can specifiy alternative seek paths if he wants...of
course, if there are formats which also support this feature, it can be
done here as well.
>
>>>> /** Tempo change or zero to skip tempo change. */
>>>> uint16_t tempo;
>>>
>>> Cryptic comment. This is the timestamp where the tempo change? An
>>> index to a list a tempo changing structures? The instrument number
>>> that has a different tempo?
>>
>> Fixed.
>>
>>>
>>>> /** Played nesting level (GoSub command maximum nesting
>>>> depth). */
>>>> uint16_t played;
>>>
>>> Again, BSS?
>>
>> Would require duplicating each track information in the player and
>> therefore add a lot of unnecessary complexity.
>
> So that means that the player _writes_ to this struct? This seems not
> optimal design in a modularity point of view. IMHO, everything that is
> feeded to the player should be read-only and the player should only
> write in his own context structure.
This would duplicate the amount of work required, i.e. duplicating the
whole order list structure. Do you think, this is worth the additional
overhead?
--
Best regards,
:-) Basty/CDGS (-:
diff --git a/libavsequencer/order.h b/libavsequencer/order.h
new file mode 100644
index 0000000..091fe7d
--- /dev/null
+++ b/libavsequencer/order.h
@@ -0,0 +1,172 @@
+/*
+ * AVSequencer order list and data management
+ * Copyright (c) 2010 Sebastian Vater <cdgs.ba...@googlemail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVSEQUENCER_ORDER_H
+#define AVSEQUENCER_ORDER_H
+
+#include "libavsequencer/track.h"
+
+/**
+ * Song order list structure, This structure is actually for one channel
+ * and therefore actually pointed as an array with size of number of
+ * host channels.
+ * New fields can be added to the end with minor version bumps.
+ * Removal, reordering and changes to existing fields require a major
+ * version bump.
+ */
+typedef struct AVSequencerOrderList {
+ /** Array (of size orders) of pointers containing all order list
+ data used by this channel. */
+ AVSequencerOrderData **order_data;
+
+ /** Number of order list data used for this channel. */
+ uint16_t orders;
+
+ /** Number of order list data entries to use for this channel. */
+ uint16_t length;
+
+ /** Repeat start order list data number for this channel. */
+ uint16_t rep_start;
+
+ /** Volume level for this channel (defaults to 255). */
+ uint8_t volume;
+#define AVSEQ_ORDER_LIST_VOLUME 255
+
+ /** Sub-volume level for this channel. This is basically channel
+ volume divided by 256, but the sub-volume doesn't account
+ into actual mixer output (defaults 0). */
+ uint8_t sub_volume;
+#define AVSEQ_ORDER_LIST_SUB_VOLUME 0
+
+ /** Stereo track panning level for this channel (defaults to
+ -128 = central stereo track panning). */
+ int8_t track_panning;
+#define AVSEQ_ORDER_LIST_TRACK_PAN -128
+
+ /** Stereo track sub-panning level for this channel. This is
+ basically track panning divided by 256, but the sub-panning
+ doesn't account into actual mixer output (defaults 0). */
+ uint8_t track_sub_panning;
+#define AVSEQ_ORDER_LIST_TRACK_SUB_PAN -128
+
+ /** Stereo panning level for this channel (defaults to
+ -128 = central stereo panning). */
+ int8_t channel_panning;
+#define AVSEQ_ORDER_LIST_PANNING -128
+
+ /** Stereo sub-panning level for this channel. This is
+ basically channel panning divided by 256, but the sub-panning
+ doesn't account into actual mixer output (defaults 0). */
+ uint8_t channel_sub_panning;
+#define AVSEQ_ORDER_LIST_SUB_PANNING 0
+
+ /** Order list playback flags. Some sequencers feature
+ surround panning or allow initial muting. which has to
+ be taken care specially in the internal playback engine.
+ Also sequencers differ in how they handle slides. */
+ uint8_t flags;
+#define AVSEQ_ORDER_LIST_FLAG_CHANNEL_SURROUND 0x01 ///< Initial channel surround instead of stereo panning
+#define AVSEQ_ORDER_LIST_FLAG_TRACK_SURROUND 0x02 ///< Initial track surround instead of stereo panning
+#define AVSEQ_ORDER_LIST_FLAG_MUTED 0x04 ///< Initial muted channel
+
+} AVSequencerOrderList;
+
+/**
+ * Song order list data structure, this contains actual order list data.
+ * New fields can be added to the end with minor version bumps.
+ * Removal, reordering and changes to existing fields require a major
+ * version bump.
+ */
+typedef struct AVSequencerOrderData {
+ /** AVSequencerTrack pointer to track which should be played. */
+ AVSequencerTrack *track;
+
+ /** Next order list data pointer if seeking forward one frame. */
+ AVSequencerOrderData *next_pos;
+
+ /** Previous order list data pointer if seeking backward one
+ frame. */
+ AVSequencerOrderData *prev_pos;
+
+ /** Number of row to jump to if forward seeking one frame. */
+ uint16_t next_row;
+
+ /** Number of row to jump to if backward seeking one frame. */
+ uint16_t prev_row;
+
+ /** Beginning row for this track. If this is a track synchronization
+ point, the high byte is interpreted as the first track number
+ to be synchronized with and the low byte as the second track
+ number or for all channels when all 4 tracks are 0. */
+ uint16_t first_row;
+
+ /** Last row for this track. If this is a track synchronization
+ point, the high byte is interpreted as the third track number
+ to be synchronized with and the low byte as the fourth track
+ number or for all channels when all 4 tracks are 0.
+ If last row is set to 65535 in non synchronization mode,
+ the last row is always taken from AVSequencerTrack. */
+ uint16_t last_row;
+
+ /** Order list data playback flags. Some sequencers feature
+ special end markers or even different playback routes for
+ different playback modules (one-shot and repeat mode
+ playback), mark synchronization points or temporary
+ change volume), which has to be taken care specially
+ in the internal playback engine. */
+ uint8_t flags;
+#define AVSEQ_ORDER_DATA_FLAG_END_ORDER 0x01 ///< Order data indicates end of order
+#define AVSEQ_ORDER_DATA_FLAG_END_SONG 0x02 ///< Order data indicates end of whole song
+#define AVSEQ_ORDER_DATA_FLAG_NOT_IN_ONCE 0x04 ///< Order data will be skipped if you're playing in one-time mode
+#define AVSEQ_ORDER_DATA_FLAG_NOT_IN_REPEAT 0x08 ///< Order data will be skipped if you're playing in repeat mode
+#define AVSEQ_ORDER_DATA_FLAG_TRACK_SYNC 0x10 ///< Order data is a track synchronization point.
+#define AVSEQ_ORDER_DATA_FLAG_SET_VOLUME 0x20 ///< Order data takes advantage of the order list volume set
+
+ /** Relative note transpose for full track. Allows playing several
+ tracks some half-tones up/down. */
+ int8_t transpose;
+
+ /** Instrument transpose. All instruments will be relatively
+ mapped to this if this is non-zero. */
+ int16_t instr_transpose;
+
+ /** Tempo change or zero to skip tempo change. A tempo value of
+ zero would be zero, since that would mean literally execute
+ unlimited rows and tracks in just one tick. */
+ uint16_t tempo;
+
+ /** Played nesting level (GoSub command maximum nesting depth). */
+ uint16_t played;
+
+ /** Track volume (this overrides settings in AVSequencerTrack).
+ To enable this, the flag AVSEQ_ORDER_DATA_FLAG_SET_VOLUME
+ must be set in flags. This allows have a basic default track
+ volume by still allowing to override the track volume in case
+ the track is used multiple times, e.g. for creating echoes. */
+ uint8_t volume;
+
+ /** Track sub-volume. This is basically track volume
+ divided by 256, but the sub-volume doesn't account
+ into actual mixer output (this overrides AVSequencerTrack). */
+ uint8_t sub_volume;
+} AVSequencerOrderData;
+
+#endif /* AVSEQUENCER_ORDER_H */
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