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Add explanation of getting non-rekordbox metadata.
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brunchboy committed Jul 21, 2018
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103 changes: 66 additions & 37 deletions doc/Analysis.tex
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Expand Up @@ -617,7 +617,7 @@ \subsection{CDJ Status Packets}
\begin{leftwordgroup}{\tiny\bfseries 20}
\bitbox{1}{\tt 03} & \bitbox{1}{$D$} & \bitboxes*{1}{{\tt 00} {\tt b0}} &
\bitbox{1}{$D$} & \bitboxes*{1}{{\tt 00} {\tt 01}} & \bitbox{1}{$A$} &
\bitbox{1}{$D_r$} & \bitbox{1}{$S_r$} & \bitbox{1}{$t_r$} & \bitbox{1}{\tt 00} &
\bitbox{1}{$D_r$} & \bitbox{1}{$S_r$} & \bitbox{1}{$T_r$} & \bitbox{1}{\tt 00} &
\bitbox{4}{$rekordbox$}
\end{leftwordgroup} \\

Expand Down Expand Up @@ -689,29 +689,30 @@ \subsection{CDJ Status Packets}
player is idle, and {\tt 01} when it is playing, searching, or loading
a track.

When a rekordbox track is loaded, the device holding the rekordbox
database from which the track was loaded is reported in $D_r$ at
byte~{\tt 28} (if the track was loaded from the local device, this
will be the same as $D$; if it was loaded over the Link, it will be
the number of a different device) When no track is loaded, $D_r$ has
the value {\tt 00}.
When a track is loaded, the device from which the track was loaded is
reported in $D_r$ at byte~{\tt 28} (if the track was loaded from the
local device, this will be the same as $D$; if it was loaded over the
Link, it will be the number of a different device) When no track is
loaded, $D_r$ has the value {\tt 00}.

Similarly, $S_r$ at byte~{\tt 29} reports the slot from which the
track was loaded: The value {\tt 00} means no track is loaded, {\tt
01} means the CD drive, {\tt 02} means the SD slot, and {\tt 03}
means the USB slot. When a track is loaded from a rekordbox collection
on a laptop, $S_r$ has the value {\tt 04}. $t_r$ at byte~{\tt 2a} may
be an indicator of whether the track came from rekordbox: It seems to
have the value {\tt 00} when no track is loaded or an unanalyzed track
is loaded, {\tt 01} when a rekordbox track is loaded, and {\tt 05}
when an audio CD is loaded.
on a laptop, $S_r$ has the value {\tt 04}. $T_r$ at byte~{\tt 2a}
indicates the track type. It has the value {\tt 00} when no track is
loaded, {\tt 01} when a rekordbox track is loaded, {\tt 02} when an
unanalyzed track is loaded (from a media slot without a rekordbox
database), and {\tt 05} when an audio CD track is loaded.

The field $rekordbox$ at bytes~{\tt 2c}--{\tt 2f} contains the
rekordbox database ID of the loaded track when a rekordbox track is
being played. Combined with the player number and slot information,
this can be used to request the track metadata as described in
Section~\ref{sec:metadata}. When an audio CD is loaded, this just
contains the track index on the disc.
being played. When a non-rekordbox media slot track is loaded, it is
still a unique ID by which the track can be identified for metadata
requests, and when an audio CD track is loaded, this is just the track
number. In all cases, combined with the player number and slot
information, this can be used to request the track metadata as
described in Section~\ref{sec:metadata}.

The track number being played (its position within a playlist or other
scrolling list of tracks, as displayed on the CDJ) can be found at
Expand Down Expand Up @@ -777,6 +778,8 @@ \subsection{CDJ Status Packets}

{\tt 09} & Player is searching forwards or backwards \\

{\tt 0e} & Audio CD has spun down due to lack of use \\

{\tt 11} & Player reached the end of the track and stopped \\

\end{longtabu}
Expand Down Expand Up @@ -1033,7 +1036,9 @@ \section{Track Metadata}
Section~\ref{sec:virtualCdj}), open a TCP connection to the device
from which the track was loaded, using the port that it gave you in
response to the DB Server query packet, then send the following four
packets.
packets. (You can also get metadata for non-rekordbox tracks, even for
CD Audio tracks being played in the CD slot, using the variation
described in Section~\ref{sec:nonRekordboxMetadata}.)

The first packet sent to the database server contains the five bytes
{\tt 11 00 00 00 01}, and results in the same five bytes being sent
Expand Down Expand Up @@ -1306,9 +1311,9 @@ \subsection{Messages}
\label{fig:querySetupResponse}
\end{figure}

\subsection{Track Metadata}
\subsection{Rekordbox Track Metadata}

To ask for metadata about a particular track, send a packet like the
To ask for metadata about a particular rekordbox track, send a packet like the
one shown in Figure~\ref{fig:trackSetupPacket}.

\begin{figure}
Expand Down Expand Up @@ -1336,12 +1341,12 @@ \subsection{Track Metadata}
\end{leftwordgroup} \\

\begin{leftwordgroup}{\tiny\bfseries 20}
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {\tt 01}} &
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {$T_r$}} &
\bitbox{1}{\tt 11} & \bitbox{4}{$rekordbox$} & \bitbox[]{6}{}
\end{leftwordgroup}

\end{bytefield}
\caption{Track metadata request message}
\caption{Rekordbox track metadata request message}
\label{fig:trackSetupPacket}
\end{figure}

Expand All @@ -1351,8 +1356,10 @@ \subsection{Track Metadata}
device that is asking the question. $S_r$ is the slot in which the
track being asked about can be found, and has the same values used in
CDJ status packets, as shown in Figure~\ref{fig:cdjStatus}. Similarly,
$rekordbox$ identifies the local rekordbox database ID of the track
being asked about, as found in the CDJ status packet.
$T_r$ identifies the type of track we want information about; for
rekordbox tracks this always has the value {\tt 01}. And $rekordbox$
identifies the local rekordbox database ID of the track being asked
about, as found in the CDJ status packet.

Track metadata requests are built on the mechanism that is used to
request and draw scrollable menus on the CDJs, so the request is
Expand Down Expand Up @@ -1433,9 +1440,7 @@ \subsection{Track Metadata}
display, is requested with a menu location number of 8 in this second
byte.

The byte after $S_r$ seems to always have the value 1. We've seen it
described as ``source analyzed'' but don't know exactly what that
means.
As described above, $T_r$ has the value 1 for rekordbox tracks.

The second argument, $offset$, specifies which menu entry is the first
one you want to see, and the third argument, $limit$, specifies how
Expand Down Expand Up @@ -1477,7 +1482,7 @@ \subsection{Track Metadata}
\end{leftwordgroup} \\

\begin{leftwordgroup}{\tiny\bfseries 20}
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {\tt 01}} &
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {$T_r$}} &
\bitbox{1}{\tt 11} & \bitbox{4}{$offset$} & \bitbox{1}{\tt 11} & \bitbox{4}{$limit$} &
\bitbox{1}{\tt 11}
\end{leftwordgroup} \\
Expand Down Expand Up @@ -1521,7 +1526,7 @@ \subsection{Track Metadata}
\end{leftwordgroup} \\

\begin{leftwordgroup}{\tiny\bfseries 20}
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {\tt 01}} &
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {$T_r$}} &
\bitbox{1}{\tt 11} & \bitbox{4}{\tt 00000000} & \bitbox{1}{\tt 11} & \bitbox{4}{\tt 0000000b} &
\bitbox{1}{\tt 11}
\end{leftwordgroup} \\
Expand Down Expand Up @@ -1875,6 +1880,29 @@ \subsection{Menu Item Types}
As noted above, track metadata responses use many of these types.
Others are used in different kinds of menus and queries.

\subsection{Non-Rekordbox Track Metadata}
\label{sec:nonRekordboxMetadata}

As noted in the introduction to this section, you can get metadata for
non-rekordbox tracks as well (although they don't have beat grids,
waveforms, or album art available). All you need to do is use a slight
variant of the metadata request message shown in
Figure~\ref{fig:trackSetupPacket}, using the value {\tt 2202} (instead
of {\tt 2002}) for the message type, and a value of $T_r$ that is
appropriate for the kind of track you are asking about ({\tt 02} for
non-rekordbox tracks loaded from media slots, and {\tt 05} for CD
audio tracks playing in the CD slot, which has a $S_r$ value of {\tt
01}). After the initial query setup message, the other message types
are the same as in the above discussion, but you will continue using
the $S_r$ and $T_r$ values appropriate for the slot and media type you
are asking about.

Since these tracks don't have rekordbox IDs, you will need to use the
$recordbox$ value reported in CDJ status packets in order to find out
the values used to request the metadata for tracks loaded from solid
state media; CD tracks are requested using the simple track number as
the $rekordbox$ value.

\subsection{Album Art}
\label{sec:albumArt}

Expand Down Expand Up @@ -2621,7 +2649,7 @@ \subsection{Requesting All Tracks}
\end{leftwordgroup} \\

\begin{leftwordgroup}{\tiny\bfseries 20}
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {\tt 01}} &
\bitbox{1}{\tt 11} & \bitboxes*{1}{{$D$} {\tt 01} {$S_r$} {$T_r$}} &
\bitbox{1}{\tt 11} & \bitbox{4}{$sort$} & \bitbox[]{6}{}
\end{leftwordgroup}

Expand All @@ -2634,14 +2662,15 @@ \subsection{Requesting All Tracks}
for the next, and so on. $D$ should have the same value you used in
your initial query context setup packet, identifying the device that
is asking the question. $S_r$ is the slot in which the track being
asked about can be found, and has the same values used in CDJ status
packets, as shown in Figure~\ref{fig:cdjStatus}. The new $sort$
parameter determines the order in which the tracks are sorted, and
that also affects the item type returned, along with the secondary
information (beyond the title) that it contains about the track, as
described in Section~\ref{sec:trackListSorting}. We will start out
assuming the tracks are being requested in title order, which can be
done by sending a $sort$ argument value of 0 or 1, and that the DJ has
asked about can be found, and $T_r$ is the type of the track; these
two bytes have the same values used in CDJ status packets, as shown in
Figure~\ref{fig:cdjStatus}. The new $sort$ parameter determines the
order in which the tracks are sorted, and that also affects the item
type returned, along with the secondary information (beyond the title)
that it contains about the track, as described in
Section~\ref{sec:trackListSorting}. We will start out assuming the
tracks are being requested in title order, which can be done by
sending a $sort$ argument value of 0 or 1, and that the DJ has
configured the media device to show artists as the second column.

Track list requests (just like metadata requests) are built on the
Expand Down
2 changes: 1 addition & 1 deletion project.clj
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@@ -1,4 +1,4 @@
(defproject dysentery "0.2.1-SNAPSHOT"
(defproject dysentery "0.2.1"
:description "Exploring ways to participate in a Pioneer Pro DJ Link network"
:url "http://github.com/brunchboy/dysentery"
:license {:name "Eclipse Public License"
Expand Down
73 changes: 38 additions & 35 deletions src/dysentery/dbserver.clj
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Expand Up @@ -326,46 +326,46 @@
know something about."
{0x0001 {:type "invalid data"}
0x1000 {:type "load root menu"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"sort order"
"magic constant?"]}
0x1002 {:type "request artist list"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"sort order?"]}
0x1004 {:type "request track list"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"sort order?"]}
0x1105 {:type "request playlist or playlist folder"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"sort order"
"playlist or folder ID"
"0=playlist, 1=folder"]}
0x2002 {:type "request track metadata"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"rekordbox ID"]}
0x2003 {:type "request album art"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"art ID"]}
0x2004 {:type "request track waveform preview"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"unknown (4)"
"rekordbox ID"
"unknown (0)"
"required declared but missing blob"]}
0x2104 {:type "request track cue points"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"rekordbox ID"]}
0x2202 {:type "request CD track data"
:arguments ["requesting player, for menu, media, analyzed (1)"
0x2202 {:type "request non-rekordbox track data"
:arguments ["requesting player, for menu, media, track type"
"track number"]}
0x2204 {:type "request beat grid information"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"rekordbox ID"]}
0x2904 {:type "request track waveform detail"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"rekordbox ID"]}
0x3000 {:type "render menu"
:arguments ["requesting player, for menu, media, analyzed (1)"
:arguments ["requesting player, for menu, media, track type"
"offset"
"limit"
"unknown (0)?"
Expand Down Expand Up @@ -495,30 +495,33 @@
(defn request-metadata
"Sends the sequence of messages that request the metadata for a
track in a media slot on the player."
[player slot track]
(let [id (swap! (:counter player) inc)
menu-field (number-field [(:number player) 1 slot 1])
setup (build-message id 0x2002 menu-field (number-field track 4))]
(print "Sending > ")
(describe-message setup)
(send-message player setup)
(when-let [response (read-message player)]
(print "Received > ")
(describe-message response)
(when (= 0x4000 (get-message-type response))
(let [item-count (get-in response [:arguments 1 :number])]
(cond
(= item-count 0xffffffff)
(timbre/error "No track with id" track "in slot" slot "on player" (:target player))
([player slot track]
(request-metadata player slot track 1))
([player slot track track-type]
(let [id (swap! (:counter player) inc)
message-type (if (= 1 track-type) 0x2002 0x2202)
menu-field (number-field [(:number player) 1 slot track-type])
setup (build-message id message-type menu-field (number-field track 4))]
(print "Sending > ")
(describe-message setup)
(send-message player setup)
(when-let [response (read-message player)]
(print "Received > ")
(describe-message response)
(when (= 0x4000 (get-message-type response))
(let [item-count (get-in response [:arguments 1 :number])]
(cond
(= item-count 0xffffffff)
(timbre/error "No track with id" track "in slot" slot "on player" (:target player))

(pos? item-count)
(let [metadata (read-menu-responses player menu-field item-count)]
;; TODO build and return more compact structure.
)
(pos? item-count)
(let [metadata (read-menu-responses player menu-field item-count)]
;; TODO build and return more compact structure.
)

:else
(timbre/error "No metadata available from player" (:target player) "slot" slot "track" track
"(are you using a valid, unused player number?)")))))))
:else
(timbre/error "No metadata available from player" (:target player) "slot" slot "track" track
"(are you using a valid, unused player number?)"))))))))

(defn request-track-list
"Sends the sequence of messages that request the track list for a
Expand Down
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