1 Interface to CD-ROM player. 2 3 This module implements an interface to the built-in cd module. The 4 intention is to provide a more user-friendly interface than the 5 built-in module. 6 7 The module defines a class Readcd with several methods. The 8 initialization of the class will try to open the CD player. This 9 means that initialization will fail if the CD player is already in 10 use. A RuntimeError will be raised by the cd module in that case. 11 12 The way to work with this module is as follows. The user specifies 13 the parts of the CD that are to be read and he specifies callback 14 functions which are to be called by the system. At some point he can 15 tell the system to play. The specified parts of the CD will then be 16 read and the callbacks will be called. 17 18 Initialization. 19 =============== 20 21 r = readcd.Readcd([cd-player [, mode]]) 22 23 The optional arguments are the name of the CD device and the mode. 24 When "mode" is not specified, it defaults to 'r' (which is the only 25 possible value); when "cd-player" also isn't specified, it defaults 26 to "None" which indicates the default CD player. 27 28 Methods. 29 ======== 30 31 eject() -- Eject the CD from the player. 32 33 reset() -- Reset the list of data stretches to be played. 34 35 appendtrack(track) -- Append the specified track to the list of music 36 stretches. 37 38 appendstretch(first, last) -- Append the stretch from "first" to "last" 39 to the list of music stretches. Both "first" and "last" can be in one 40 of four forms. "None": for "first", the beginning of the CD, for 41 "last" the end of the CD; a single integer: a track number--playing 42 starts at the beginning of the track or ends at the end of the 43 specified track; a three-tuple: the absolute time from the start of 44 the CD in minutes, seconds, frames; a four-tuple: track number and 45 relative time within the track in minutes, seconds, frames. 46 47 settracks(tracklist) -- The argument is a list of integers. The list 48 of stretches is set to argument list. The old list is discarded. 49 50 setcallback(type, func, arg) -- Set a callback function for "type". 51 The function will be called as func(arg, type, data) where "arg" is 52 the third argument of setcallback, "type" is the type of callback, 53 "data" is type-dependent data. See the CDsetcallback(3) manual page 54 for more information. The possible "type" arguments are defined in 55 the CD module. 56 57 removecallback(type) -- Remove the callback for "type". 58 59 gettrackinfo([tracklist]) -- Return a list of tuples. Each tuple 60 consists of start and length information of a track. The start and 61 length information consist of three-tuples with minutes, seconds and 62 frames. The optional tracklist argument gives a list of interesting 63 track numbers. If no tracklist is specified, information about all 64 tracks is returned. 65 66 getstatus() -- Return the status information of the CD. 67 68 play() -- Play the preprogrammed stretches of music from the CD. When 69 nothing was programmed, the whole CD is played. 70 71 Specifying stretches. 72 ===================== 73 74 There are three methods available to specify a stretch of music to be 75 played. The easiest way is to use "settracklist(tracklist)" with which 76 a list of tracks can be specified. "settracklist(tracklist)" is 77 equivalent to the sequence 78 reset() 79 for track in tracklist: 80 appendtrack(track) 81 82 The next method is "appendtrack(track)" with which a whole track can be 83 added to the list of music to be played. "appendtrack(track)" is 84 equivalent to "appendstretch(track, track)". 85 86 The most complete method is "appendstretch(first, last)". Using this 87 method, it is possible to specify any stretch of music. 88 89 When two consecutive tracks are played, it is possible to choose 90 whether the pause that may be between the tracks is played as well or 91 whether the pause should be skipped. When the end of a stretch is 92 specified using a track number and the next stretch starts at the 93 beginning of the following track and that was also specified using the 94 track number (that is, both were specified as integers, not as tuples), 95 the pause is played. When either value was specified using absolute 96 time or track-relative time (that is, as three-tuple or as 97 four-tuple), the pause will not be played. 98 99 Errors. 100 ======= 101 102 When an error occurs, an exception will be raised. Depending on where 103 the error occurs, the exception may either be "readcd.Error" or 104 "RuntimeError". 105