[FFmpeg-soc] [soc] libavsequencer [PATCH 01/08] Music module public API header file.

[Sebastian Vater]

Stefano Sabatini a écrit :
>> +
>> +/**
>> + * Sequencer module structure.
>> + * New fields can be added to the end with minor version bumps.
>> + * Removal, reordering and changes to existing fields require a major
>> + * version bump.
>> + */
>>     
>
> Please describe the general architecture for libavsequencer.  It looks
> really complex, and we need to understand how the various components
> iteract. In particular we need to understand how a mod decoder can be
> built and integrated into FFmpeg.
>   

avsequencer.h will follow the next days. ;)

This file is just about the actual module. Not the generic architecture
which will all go into lavs/avsequencer.h

> In particular we need to understand which will be the role of the
> player, which will likely be the first component to be reviewed.
>   

All what is solely belonging to the player will go into lavs/player.h

lavs/(module/song/order/track/instr/sample/synth).h will be both for
editors and players.

>   
>> +typedef struct AVSequencerModule {
>> +    /** Metadata information: Original module file name, module name,
>> +     *  module message, artist, genre, album, begin and finish date of
>> +     * composition and comment.  */
>> +    AVSequencerMetadata *metadata;
>>     
>
> AVSequencerMetadata is not shown in your patches, also I wonder, won't
> be this a repetition of libavformat AVMetaData?
>   

In most terms, yes, but some data is not available in AVMetadata (like
module file name and start and finish date of composition).

I was looking at it, before I decided to use AVSequencerMetadata or
AVMetadata. But maybe it's really a better solution to add these fields
to AVMetadata directly?

>   
>> +
>> +    /** AVSequencerPlayerChannel pointer to virtual channel data.  */
>> +    AVSequencerPlayerChannel *channel_data;
>>     
>
> Same I cannot see definition for this.
>   

See lavs/player.h (PATCH 08/08), all typedef struct's starting with
AVSequencerPlayer* are in player.h ;-)

>> +    /** Integer indexed tree root of sub-songs available in
>> +       this module with AVTreeNode->elem being a AVSequencerSong.  */
>> +    AVTreeNode *song_list;
>> +
>> +    /** Integer indexed tree root of instruments available for
>> +       the whole module (shared between all sub-songs) with
>> +       AVTreeNode->elem being a AVSequencerInstrument.  */
>> +    AVTreeNode *instrument_list;
>> +
>> +    /** Integer indexed tree root of envelopes used by module
>> +       with AVTreeNode->elem being a AVSequencerEnvelope.
>> +       There can be vibrato, tremolo, panbrello, spenolo,
>> +       volume, panning, pitch, envelopes, a resonance filter and
>> +       finally the auto vibrato, tremolo and panbrello envelopes.  */
>> +    AVTreeNode *envelopes_list;
>> +
>> +    /** Integer indexed tree root of keyboard definitions
>> +       with AVTreeNode->elem being a AVSequencerKeyboard.
>> +       A keyboard definition maps an instrument octave/note-pair
>> +       to the sample number being played.  */
>> +    AVTreeNode *keyboard_list;
>> +
>> +    /** Integer indexed tree root of arpeggio envelopes
>> +       with AVTreeNode->elem being a AVSequencerArpeggioEnvelope.
>> +       Arpeggio envelopes allow to fully customize the arpeggio
>> +       command by playing the envelope instead of only a 
>> +       repetive set of 3 different notes.  */
>> +    AVTreeNode *arp_env_list;
>> +
>> +    /** Duration of the module, in AV_TIME_BASE fractional
>> +       seconds. This is the total sum of all sub-song durations
>> +       this module contains.  */
>> +    uint64_t duration;
>> +
>> +    /** Maximum number of virtual channels, including NNA (New Note
>> +       Action) background channels to be allocated and processed by
>> +       the mixing engine (defaults to 64).  */
>> +    uint16_t channels;
>> +#define AVSEQ_MODULE_CHANNELS   64
>> +
>> +    /** Compatibility flags for playback. There are rare cases
>> +       where effect handling can not be mapped into internal
>> +       playback engine and have to be handled specially. For
>> +       each module which needs this, this will define new
>> +       flags which tag the player to handle it to that special
>> +       way.  */
>> +    int8_t compat_flags;
>> +
>> +    /** Module playback flags.  */
>> +    int8_t flags;
>> +
>> +    /** 64-bit integer indexed unique key tree root of unknown data
>> +       fields for input file reading with AVTreeNode->elem being
>> +       unsigned 8-bit integer data. Some formats are chunk based
>> +       and can store information, which can't be handled by some
>> +       other, in case of a transition the unknown data is kept as
>> +       is. Some programs write editor settings for module in those
>> +       chunks, which won't get lost then. The first 8 bytes of this
>> +       data is an unsigned 64-bit integer length in bytes of
>> +       the unknown data.  */
>> +    AVTreeNode *unknown_data;
>> +
>> +    /** This is just a data field where the user solely
>> +       decides, what the usage (if any) will be.  */
>> +    uint8_t *user_data;
>> +
>> +} AVSequencerModule;
>> +
>>     
>
>   
>> +/**
>> + * Registers a module to the AVSequencer.
>>     
>
> Register, as per the new style.
>   

Fixed locally.

>   
>> + *
>> + * @param module the AVSequencerModule to be registered
>> + * @return >= 0 on success, error code otherwise
>> + *
>> + * @NOTE This is part of the new sequencer API which is still under construction.
>>     
>
> @note (case is meaningful).
>   

Oooops...fixed locally!

Please note I can't commit fixes to github (see my eMail) anymore since
git rebase -i! Please see my mail. So for now, fixed only locally.

-- 

Best regards,
                   :-) Basty/CDGS (-: