X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/6d2d327ca57fefaddceba10eb323451f8150e95d..e7eb3a2744aa45179daea235800753d3d1955338:/server/speaker.h

diff --git a/server/speaker.h b/server/speaker.h
index 9a48ca6..0cc0cb8 100644
--- a/server/speaker.h
+++ b/server/speaker.h
@@ -1,21 +1,19 @@
 /*
  * This file is part of DisOrder
- * Copyright (C) 2005, 2006, 2007 Richard Kettlewell
+ * Copyright (C) 2005-2008 Richard Kettlewell
  *
- * This program is free software; you can redistribute it and/or modify
+ * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- * USA
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 /** @file server/speaker.h
  * @brief Speaker process
@@ -46,13 +44,14 @@
 #define FRAMES 4096
 
 /** @brief Bytes to send per network packet
+ *
+ * This is the maximum number of bytes we pass to write(2); to determine actual
+ * packet sizes, add a UDP header and an IP header (and a link layer header if
+ * it's the link layer size you care about).
  *
  * Don't make this too big or arithmetic will start to overflow.
  */
-#define NETWORK_BYTES (1024+sizeof(struct rtp_header))
-
-/** @brief Maximum RTP playahead (ms) */
-#define RTP_AHEAD_MS 1000
+#define NETWORK_BYTES (1500-8/*UDP*/-40/*IP*/-8/*conservatism*/)
 
 /** @brief Maximum number of FDs to poll for */
 #define NFDS 256
@@ -87,6 +86,14 @@ struct track {
   /** @brief Slot in @ref fds */
   int slot;
 
+  /** @brief Set when playable
+   *
+   * A track becomes playable whenever it fills its buffer or reaches EOF; it
+   * stops being playable when it entirely empties its buffer.  Tracks start
+   * out life not playable.
+   */
+  int playable;
+  
   /** @brief Input buffer
    *
    * 1Mbyte is enough for nearly 6s of 44100Hz 16-bit stereo
@@ -135,11 +142,9 @@ struct speaker_backend {
    * If it is @ref device_closed then the device should be opened with
    * the right sample format.
    *
-   * Some devices are effectively always open and have no error state,
-   * in which case this callback can be NULL.  In this case @ref
-   * FIXED_FORMAT must be set.  Note that @ref device_state still
-   * switches between @ref device_open and @ref device_closed in this
-   * case.
+   * Some devices are effectively always open and have no error state, in which
+   * case this callback can be NULL.  Note that @ref device_state still
+   * switches between @ref device_open and @ref device_closed in this case.
    */
   void (*activate)(void);
 
@@ -165,12 +170,20 @@ struct speaker_backend {
   void (*deactivate)(void);
 
   /** @brief Called before poll()
+   * @param timeoutp Pointer to timeout
+   *
+   * Called before the call to poll().
+   *
+   * If desirable, should call addfd() to update the FD array and stash the
+   * slot number somewhere safe.  This will only be called if @ref device_state
+   * is @ref device_open.
+   *
+   * @p timeoutp points to the poll timeout value in milliseconds.  It may be
+   * reduced, but never increased.
    *
-   * Called before the call to poll().  Should call addfd() to update
-   * the FD array and stash the slot number somewhere safe.  This will
-   * only be called if @ref device_state = @ref device_open.
+   * NB you can NOT assume that @c beforepoll is always called before @c play.
    */
-  void (*beforepoll)(void);
+  void (*beforepoll)(int *timeoutp);
 
   /** @brief Called after poll()
    * @return 1 if output device ready for play, 0 otherwise
@@ -214,6 +227,8 @@ extern struct track *playing;
 extern const struct speaker_backend network_backend;
 extern const struct speaker_backend alsa_backend;
 extern const struct speaker_backend command_backend;
+extern const struct speaker_backend coreaudio_backend;
+extern const struct speaker_backend oss_backend;
 
 extern struct pollfd fds[NFDS];
 extern int fdno;