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Library
Module
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Parameter
Class
Class type
package ogg
Ogg stream demuxer
This module provides a functional abstract API to * decode and seek in Ogg streams. * * Decoders are also provided in ocaml-vorbis, * ocaml-speex, ocaml-schroedinger, ocaml-flac and * ocaml-theora. * * Functions in this module are not thread safe!
Decoding
Types
Type for a decodable track. * First element is a string describing * the decoder used to decode the track. * Second element is the serial number * associated to the Ogg.Stream.stream logical * stream used to pull data packets for that * track.
Type for standard tracks (see get_standard_tracks below).
Type for metadata. First element * is a string describing the vendor, second * element is a list of metadata of the form: * (label,value).
type video_plane =
(int, Bigarray.int8_unsigned_elt, Bigarray.c_layout) Bigarray.Array1.tType of a video plane.
Supported video formats.
type video_data = {format : video_format;frame_width : int;frame_height : int;y_stride : int;(*Length, in bytes, per line
*)uv_stride : int;(*Length, in bytes, per line
*)y : video_plane;(*luminance data
*)u : video_plane;(*Cb data
*)v : video_plane;(*Cr data
*)
}Type for video data.
Exceptions
Initialization functions
Initiate a decoder with the given callbacks. * log is an optional functioned used to * return logged messages during the deocding * process.
val init_from_file : ?log:(string -> unit) -> string -> t * Unix.file_descrInitiate a decoder from a given file name.
val init_from_fd : ?log:(string -> unit) -> Unix.file_descr -> tInitate a decoder from a given Unix.file_descriptor
val get_ogg_sync : t -> Ogg.Sync.tGet the Ogg.Sync handler associated to * the decoder. Use only if know what you are doing.
val reset : t -> unitReset encoder, try to parse a new sequentialized stream. * To use when end_of_stream has been reached.
val abort : t -> unitConsume all remaining pages of the current * stream. This function may be called to skip * a sequentialized stream but it may be quite * CPU intensive if there are many pages remaining.. * * eos dec is true after this call.
val eos : t -> booltrue if the decoder has reached the end of each * logical streams and all data has been decoded. * * If you do not plan on decoding some data, * you should use drop_track to indicate it * to the decoder. Otherwise, eos will return * false until you have decoded all data.
val get_standard_tracks : t -> standard_tracksGet the first available audio and * video tracks and drop the other one.
val update_standard_tracks : t -> standard_tracks -> unitUpdate a given record of standard tracks. You should * use this after a reset to update the standard tracks * with the newly created tracks.
Information functions
val audio_info : t -> track -> audio_info * metadataGet informations about the * audio track.
val video_info : t -> track -> video_info * metadataGet informations about the * video track.
Get the sample_rate of the track * of that type. Returns a pair (numerator,denominator).
val get_position : t -> floatGet absolute position in the stream.
Seeking functions
val can_seek : t -> boolReturns true if the decoder * can be used with the seek function.
val seek : ?relative:bool -> t -> float -> floatSeek to an absolute or relative position in seconds. * * Raises Not_available if seeking is * not possible. * * Raises End_of_stream if the end of * current stream has been reached while * seeking. You may call reset in this * situation to see if there is a new seqentialized * stream available. * * Returns the time actually reached, either in * relative time or absolute time.
Decoding functions
val decode_audio : t -> track -> (audio_data -> unit) -> unitDecode audio data, if possible. * Decoded data is passed to the second argument. * * Raises End_of_stream if all stream have ended. * In this case, you can try reset to see if there is a * new sequentialized stream.
val decode_video : t -> track -> (video_data -> unit) -> unitDecode video data, if possible. * Decoded data is passed to the second argument. * * Raises End_of_stream if all streams have ended. * In this case, you can try reset to see if there is a * new sequentialized stream.
Implementing decoders
Types
type ('a, 'b) decoder = {name : string;info : unit -> 'a * metadata;decode : ('b -> unit) -> unit;restart : Ogg.Stream.stream -> unit;(*This function is called after seeking * to notify the decoder of the new
*)Ogg.Stream.stream* that is should use to pull data packets.samples_of_granulepos : Int64.t -> Int64.t;
}Generic type for a decoder.
type decoders = | Video of (video_info, video_data) decoder| Audio of (audio_info, audio_data) decoder| Unknown
Type for a generic logical stream decoder.
type register_decoder =
(Ogg.Stream.packet -> bool) * (Ogg.Stream.stream -> decoders)Type used to register a new decoder. First * element is a function used to check if the initial Ogg.Stream.packet * of an Ogg.Stream.stream matches the format decodable by this decoder. * Second element is a function that instanciates the actual decoder * using the initial Ogg.Stream.stream used to pull data packets for the * decoder.
Functions
val ogg_decoders : (string, register_decoder) Hashtbl.tRegister a new decoder.