1 This file documents the ``Extended'' VLC Video CD Plugin
3 Copyright (C) 2003, 2004 Rocky Bernstein (rocky@panix.com)
5 Permission is granted to copy, distribute and/or modify this document
6 under the terms of the GNU Free Documentation License, Version 1.1 or
7 any later version published by the Free Software Foundation; with the
8 Invariant Sections being ``Free Software'' and ``Free Software Needs
9 Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
10 and with the Back-Cover Texts as in (a) below.
12 (a) The Free Software Foundation's Back-Cover Text is: ``You have
13 freedom to copy and modify this GNU Manual, like GNU software. Copies
14 published by the Free Software Foundation raise funds for GNU
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19 -----------------------------------------------------------------
21 The newer Video CD plugin (using libcdio and vcdimager) has some
22 navigation and playback capabilities. However full integration with
23 into vlc is a bit lacking and will probably take some a bit of work
26 Although, this plugin replaces the older VCD plugin, the old plugin is
27 still built and installed and used when the newer plugin is not found.
29 This document describes only the newer VCD plugin.
31 The next section is a general overview of Video CD's in general. If
32 you are in a hurry to find out how to use this plugin or know this
33 already, this section can be skipped.
35 After that we describe the terms and concepts used in the remainder
36 Again, in a hurry, this section can be skipped or skimmed. If you come
37 across a term like "segment," or "lid" that confuses you, look in
40 The next section describes the MRL format that this plugin uses. If
41 you want to know how to control where to start playing, read this.
42 Even if you are familiar with vlc MRL's, you probably want to look
43 at this section. Some of the units in a VCD are a little different
44 than those in a DVD or audio CD.
46 The next section gives key bindings that are used by this
47 plugin. Again to be able to control the plugin, especially for
48 playback control, you may need to read this section.
50 The next section describes the configuration parameters you can set
51 for the plugin. Most of the default values I hope are what most
52 people will want to start out with. But for fine control of the
53 defaults, read this section.
55 One configuration variable is the debug output. The next section
56 describes the meaning of debug flags and how to troubleshoot the
59 -----------------------------------------------------------------
60 About VCDs, SVCDs, and XVCDs.
61 -----------------------------------------------------------------
62 From: http://www.vcdhelp.com/vcd
64 VCD stands for 'Video Compact Disc' and basically it is a CD that
65 contains moving pictures and sound. If you're familiar with regular
66 audio/music CDs, then you will know what a Video CD looks like. A VCD
67 has the capacity to hold up to 74/80 minutes on 650MB/700MB CDs
68 respectively of full-motion video along with quality stereo
69 sound. VCDs use a compression standard called MPEG to store the video
70 and audio. A VCD can be played on almost all standalone DVD Players
71 and of course on all computers with a DVD-ROM or CD-ROM drive with
72 the help of a software based decoder / player. It is also possible to
73 use menus and chapters, similar to DVDs, on a VCD and also simple
74 photo album/slide shows with background audio. The quality of a very
75 good VCD is about the same as a VHS tape based movie but VCD is
76 usually a bit more blurry. If you want better quality checkout
79 From: http://www.vcdhelp.com/svcd.htm
81 SVCD stands for "Super VideoCD". A SVCD is very similar to a VCD, it
82 has the capacity to hold about 35-60 minutes on 74/80 min CDs of very
83 good quality full-motion video along with up to 2 stereo audio tracks
84 and also 4 selectable subtitles. A SVCD can be played on many
85 standalone DVD Players and of course on all computers with a DVD-ROM
86 or CD-ROM drive with the help of a software based decoder / player. It
87 is also possible to use menus and chapters, similar to DVDs, on a
88 SVCD and also simple photo album/slide shows with background
89 audio. The quality of a SVCD is much better than a VCD, especially
90 much more sharpen picture than a VCD because of the higher
91 resolution. But the quality depends how many minutes you choose to
92 store on a CD, less minutes/CD generally means higher quality.
94 From: http://www.vcdhelp.com/xvcd.htm
96 XVCD stands for eXtendedVCD. XVCD has same features as VCD but it is
97 possible to use higher bitrates and higher resolution to get higher
98 video quality. XVCD is basicly everything that uses MPEG1 video, is
99 not within the VCD standard and burnt in "VCD"-Mode.
101 XSVCD stands for eXtendedSVCD. XSVCD has same features as SVCD but it
102 is possible to use higher bitrates and higher resolution to get
103 higher video quality. XSVCD is basicly everything that uses MPEG2
104 video, is not within the SVCD standard and burnt in "SVCD"-Mode.
107 -----------------------------------------------------------------
108 Concepts used by this plugin.
109 -----------------------------------------------------------------
111 The remote control of a Video CD players (or the front panel)
112 generally has special keys or buttons. The author of a Video CD can
113 assign what action to use when these buttons are pressed. They buttons
116 RETURN: Often used to return to the previous menu or previouly
117 interruped video segment.
119 DEFAULT: Possibly take the default selection value. This function can
120 only be assigned when the LID refers to in a "Program Selection List"
121 or "Extended Program Selection List"
123 NEXT: Possibly the next entry, chapter, track, or menu.
125 PREVIOUS: Possibly the previous entry, chapter, track, or menu.
127 Contiguous non-overlapping regions of a Compact Disc are called
128 "Tracks". The sum of the tracks forms the entire CD. The CD
129 specifications standards say that between tracks there is to be a
132 In the MRL list described below, we generally don't list the first
133 track which we would call call "Track 0", but other tools like
134 VCDimager, cdinfo, and the CD-reading world in the general call this
135 "Track 1". This first track usually contains an ISO 9660-format
136 filesystem with metadata describing what's on the CD. It may also
137 contain "segments" or small MPEGs that generally make up still frames
138 and menus. Aside from the segments which are merely only parts of
139 track 0, it doesn't make sense to try to "play" track 0 (or track 1
140 depending on how you want to count), which is why we don't list it.
141 It seems natural to call the first thing you would want to play "track
142 1" (which in fact is track 2 to everyone else).
144 There are two other units that this plugin lists and are used
145 internally. One we call an "entry". This is a starting point of a
146 track which can include the beginning of the track, and when an entry
147 points to the beginning of a track, it is equivalent to listing the
148 track. However Video CD's often have multiple entry points into a
149 track. Logically this corresponds to a "Chapter" or "Scene" of a
150 larger uninterruptable unit. One might think a CD "track" could serve
151 this purpose with a collection of tracks making up a work or
152 movie. Alas, there is "track pregap" space between tracks which appear
153 as a time gaps when hardware players go between tracks - something
154 that doesn't have to happen switching between entries because there in
157 Another unit we use is a called a "segment." These are just the
158 playable units in track 0. Segments come in fixed-length units so
159 several may be combined to form a single logical playable unit. Still
160 frames for menus are segments. A menu doesn't have to have a
161 still-frame associated with it; a menu might be implemented as a short
162 looped movie clip. But all still frames are segments. Also, Video CD
163 specifications allow still frames to have higher resolution than
164 motion clips. All segments reside in track 0.
166 A "list ID" (also called a LID and and is one greater than a Play
167 Sequence descripter or "PSD" number) combines "entries" and "segments"
168 and "tracks" together with some navigation logic. "Playback Control"
169 (acronym PBC) is simply starting playback at a particular LID, and
170 unless otherwise specified you'd start with the first playback item
173 Below we will refer to an "item" as combination of a unit name (track,
174 entry, segment, playback) and a whole number.
176 -----------------------------------------------------------------
178 -----------------------------------------------------------------
180 This vlc Video CD plugin, identifies itself in the vlc GUI preferences
181 vcdx. It also registers itelf to handle a class of MRL's that start
184 The VCDX MRL takes the following form:
186 vcdx://[path to file or vcd device][@[letter]number]]
188 (Note: eventually the trailing "x" will be dropped. In MRL's "vcd"
189 works as well as "vcdx".
191 A simple vcdx:// runs the default item (e.g. perhaps track 1 or the
192 playback control) the default VCD device (perhaps /dev/cdrom). Whether
193 to use playback control and the default device are user-configurable.
195 It is however also possible to specify both Video CD device/filename
196 and the kind of item explicitly in the MRL.
198 For example vcdx:/dev/dvd specifies the default entry using device
199 /dev/dvd which might useful if this is your DVD which is different
200 than your CD-ROM device and your DVD drive can play CD's. And
201 vcdx://test_svcd_ntsc.cue specifies the cue file for CD image on disk.
202 (test_svcd_ntsc.bin is the corresponding bin file, but using that
205 After the optional device name or file name, you can name the kind of
206 unit which preceded by an '@'. An MRL which ends in an @ is like
207 not adding it at all: the default entry type and number is used. Items
208 come in 4 flavors: "Track," "Entry," "Playback," and "Segment." See
209 the preceding section for an explaination of these terms. These units
210 are indicated with the capital first letter of each type: T, E, P, S,
213 --- In the future when we are able to control MRL display:
214 An uppercase S in the MRL display indicates a NTS segment while a
215 lowercase S indicates a PAL segment.
218 However when you enter a MRL, the case of these letters is
221 You can configure various things that affect MRLs are selected when
222 there is some ambiguity in the MRL name. vcdx-PBC sets whether to
223 to use PBC in a MRL is none is given. Another configuration
224 setting, vcdx-device, determines what device to use if that part is
227 Some examples of MRLS are given below. In the examples, we assume the
228 following configuration settings:
231 vcdx-device=/dev/cdrom
233 vcdx:// - Play (navigate) default item (in this
234 case Entry ID 0) from the default device (in this
235 case set to /dev/cdrom)
236 vcdx://@ - same as above
237 vcdx:///dev/cdrom@ - same effect as above since the default device
238 is set to /dev/cdrom.
239 vcdx:///dev/cdrom@E0 - same as above. But note that this is
240 because we have autoplay:entry which is
241 no longer the default value
242 vcdx:///dev/cdrom2@ - Play (navigate) the default item of /dev/cdrom2
243 vcdx:///dev/cdrom2 - should be same as above but is currently broken?
244 vcdx:///dev/cdrom2@T1 - Play Track 1 from /dev/cdrom2
245 vcdx:///dev/cdrom@S1 - Play segment 1 from /dev/cdrom. This
246 assumes there *is* a segment 1. Check
247 the MRL list to see if that is the case.
248 vcdx://@P1 - Play LID item 1 from default device
249 If there is no playback control, MRL will
250 get converted into vcdx://@E0. Again
251 check the MRL list to see if there is a P1.
252 vcdx://@P1* - probably same as above.
253 vcdx:///dev/cdrom@E1 - Play Entry id 1 from default device
254 vcdx://@S0 - Play segment 0 from default device
255 vcdx://@3 - Play track 3 from default device
256 vcdx:///dev/cdrom2:1 - Play track 1 from /dev/cdrom2
257 vcdx:///tmp/ntsc.cue@ - Play default item (E0) of /tmp/ntsc.bin. Note
259 vcdx://ntsc.cue/@E0 - Play entry 0 of ntsc.bin
260 vcdx:///tmp/ntsc.nrg/@E0 - Play entry 0 of /tmp/ntsc.nrg (Nero
261 file) Works for some simple Nero images.
263 -----------------------------------------------------------------
264 Key bindings and non-PBC navigation.
265 -----------------------------------------------------------------
267 At present vlc doesn't have special hot-keys for "NEXT", "PREVIOUS",
268 "RETURN" or "DEFAULT". So we use some of other hot-key names that
269 don't seem to correspond to anything for a VCD. The key mapping names
273 --------------------------
275 NAVIGATE DOWN DEFAULT
276 NAVIGATE LEFT PREVIOUS
279 Also this plugin understand numeric input. Since the hot-keys don't
280 have assignments for numbers, the digits on the keyboard (also
281 available from the keypad if num-lock is on) are hard-coded. Even
282 though this isn't customizable, it's probably what most people would
285 The enter a number just type the digits of the number. To finish
286 specifying a number use the whatever key is bound to vlc's
287 "ACTIVATE" hot key - the default value is the "Enter" key.
289 However the next/previous/return buttons can be prefaced with a number
290 and that has the effect of hitting that button that many times. So
291 let's say you want to go forward 5 "Chapters" and hitting the "Next"
292 key 5 times would do that Instead, you could just enter the digit 5
293 followed by the key that is assigned to "NAVIGATE RIGHT", probably the
296 If you have better suggestions as to what functions the VCD buttons
297 would be better bound to how what fixed algorithm to use when not in
300 -----------------------------------------------------------------
301 Configuration settings:
302 -----------------------------------------------------------------
304 Configuration settings in xine are generally put in ~/.vlc/vlcrc, but
305 can be configured via a vlc GUI. A description of the ones specific to
306 VCDX are listed below.
312 This specifies the name of the video device that will be used by default.
313 If you don't specify anything, the plugin scan for a suitable CD-ROM
314 device containing a Video CD in it.
316 The default device in a MRL when none is listed. The default is
317 determined by the appropriate name for the OS that you are running.
323 An integer (interpreted as a bit mask) which shows additional
324 debugging information see the Debugging Section below for more
325 information about the bits that can be set.
327 -----------------------------------------------------------------
328 Troubleshooting Guide
329 -----------------------------------------------------------------
331 The VCD plugin leaves a bit to be desired and has many bugs. I expect
332 that there will not be covered below. But the below is a start.
334 This gives higher-level troubleshooting. More detailed and
335 lower-level information is given in the next section DEBUGGING.
337 1. Do you even have the plugin loaded?
339 When you run the vlc GUI, under Settings/Preferences you should see
340 a "plugins" expandable list and under that another "access" list do
341 you see a expandalbe entry under "access" labeled "vcdx"? If so,
344 a) If no "vcdx" expandable list, thent the VCDX plugin isn't
345 loaded. Does a shared object exist? The plugin shared object is
346 called "libvcdx_plugin.so" It should be in the directory that has
347 ...vlc/access. If this isn't around you need to build and install
350 b) if libvcdx_plugin.so is in the fileystem, there might be a
351 loader error; perhaps libcdio or libvcdinfo are not installed or
352 are the wrong version. Use ldd on the file to see that it has all
353 of the libraries dependencies satisfied. Also you might be able
354 check if there was an attempt to load it by tracking system
355 calls. On Linux and other OS's) "strace" can be used to see if the
356 file gets accessed. On Solaris use "truss".
358 For example on Linux, amonst the many line of output when I run
359 "strace -e trace=file vlc" I see this amongst lots of other
363 stat64("/usr/local/lib/vlc/access/libvcdx_plugin.so", {st_mode=S_IFREG|0755, st_size=302990, ...}) = 0
364 open("/usr/local/lib/vlc/access/libvcdx_plugin.so", O_RDONLY) = 5
366 The parameters inside the calls may be different depending on where
367 vlc is installed and what release is installed. If the the file is
370 There may also be a message may under "setup/logs".
372 2. (There plugin was loaded and preferences found). In the "vcdx" tab
373 of preference. An important selection is "vcdx-device." If this is
374 set to the empty string, VCDX will try to scan your drives for a
375 suitable device if the driver has the capability to scan for
376 drives. However you can set the device to something of your
377 choosing. On GNU/Linux, this may be "/dev/cdrom" and on Solaris it
378 may be "/vol/dev/aliases/cdrom0". If you set this field, make sure
379 these are correct for your particular setup. For example, I
380 generally play out of the DVD device and this is called /dev/dvd
381 rather than /dev/cdrom.
383 3. (Video CD Setup devices seems correct and there is a CD in the
389 you should see your CD disk light go on if you have one. And the CD
392 a. If not something's wrong like step 2. Another tack may be to try
393 to read a disk image of a Video CD and thus elimate any problems
394 with hardware. You can get a test Video CD disk image to test here:
396 http://www.vcdimager.org/pub/vcdimager/examples/test_svcd/test_svcd_pal.zip
398 After unzipping this run there should be files test_svcd_pal.cue
399 and test_svcd_pal.bin. Get out of xine and run from the directory
400 that contains those files:
401 vcdx://test_svcd_pal.cue@E0
403 If you see something playing then this is a hardware problem.
405 -----------------------------------------------------------------
407 -----------------------------------------------------------------
409 **General vlc debugging...
411 Before delving to things specific to this plugin, some preparation may
412 be in order. You'll probably want to configure vlc with "--enable-debug".
413 plugin with debug information. Instead of "make'ing" with "make", use
414 "make debug" and instead of installing using "make install" use "make
417 I use gdb to debug. Debugging vlc with the entire suite of plugins
418 under gdb is slow because it has to read in symbol tables from all the
419 plugins. There are two ways to make loading faster when debugging. The
420 simplest is just to go to the plugin directory and remove unused
421 plugins. Another approach is create a new directory and make
422 (symbolic) links into the complete plugin directory. Another way to
423 speed up gdb loading is to attach the debugger after vlc has started up
426 gdb -p *pid-of-vlc-process*
431 It's a fact of life that this plugin is in an incomplete state and has
432 bugs. So to facilitate tracking down problems we let you see what's
433 going on dynamically. Various debugging settings will cause output to
434 appear on vlc plugin log and/or "standard error" (assuming you've run
435 xine in a way that you can capture this).
437 You think of debug switches as a bit mask, that you specifiy as an
438 integers the various "bit" values (given in decimal) are listed below.
440 name value description
441 ------ ---------- -----------
442 meta info 1 Trace Meta information
443 event info 2 Trace keyboard events
444 MRL 4 Things involved getting lists of what's in the VCD
445 ext call 8 Trace vlc calls to the plugin routines
446 all calls (10) 16 Trace all calls
447 LSN (20) 32 Trace updates to the Logical sector number
449 PBC (40) 64 Trace things involved with playback control
450 libcdio (80) 128 Turn on CDIO debugging
451 seek-set (100) 256 Trace "seek set" calls
452 seek-cur (200) 512 Trace "seek cur" calls
453 still (400) 1024 Trace Still-frames
454 vcdinfo (800) 2048 Turn on VCDINFO debugging
457 **Video CD debugging...
459 The tool vcd-info from the cdio branch of vcdimager can be used to
460 show the entire contents of a Video CD or selected portions of
461 that. Until the cdio branch of vcdimager is completely merged with
462 vcdimager, the cd-info branch vresion has a few more
463 features. (However consult vcdimager for complete of the program).
465 vcdxrip can be used to extract portions of a Video CD and or create an
466 XML description file of the Video CD. This XML file and the extracted
467 files can be used by vcdxbuild to recreate another Video CD.
469 And finally see also tools cd-info an cd-read from libcdio.
471 -----------------------------------------------------------------
473 -----------------------------------------------------------------
474 http://www.vcdhelp.com/
475 http://www.vcdimager.org/
476 http://www.vcdimager.org/guides/#guides
478 $Id: intf-vcd.txt,v 1.3 2004/01/25 14:18:40 rocky Exp $
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