lavf: add SBG demuxer.

Changelog

@@ -136,6 +136,7 @@ easier to use. The changes are:
 - Dxtory capture format decoder
 - cellauto source
 - v410 Quicktime Uncompressed 4:4:4 10-bit encoder and decoder
+- SBaGen (SBG) binaural beats script demuxer
 
 
 version 0.8:

doc/demuxers.texi

@@ -75,4 +75,34 @@ the caller can decide which variant streams to actually receive.
 The total bitrate of the variant that the stream belongs to is
 available in a metadata key named "variant_bitrate".
 
+@section sbg
+
+SBaGen script demuxer.
+
+This demuxer reads the script language used by SBaGen
+@url{http://uazu.net/sbagen/} to generate binaural beats sessions. A SBG
+script looks like that:
+@example
+-SE
+a: 300-2.5/3 440+4.5/0
+b: 300-2.5/0 440+4.5/3
+off: -
+NOW      == a
++0:07:00 == b
++0:14:00 == a
++0:21:00 == b
++0:30:00    off
+@end example
+
+A SBG script can mix absolute and relative timestamps. If the script uses
+either only absolute timestamps (including the script start time) or only
+relative ones, then its layout is fixed, and the conversion is
+straightforward. On the other hand, if the script mixes both kind of
+timestamps, then the @var{NOW} reference for relative timestamps will be
+taken from the current time of day at the time the script is read, and the
+script layout will be frozen according to that reference. That means that if
+the script is directly played, the actual times will match the absolute
+timestamps up to the sound controller's clock accuracy, but if the user
+somehow pauses the playback or seeks, all times will be shifted accordingly.
+
 @c man end INPUT DEVICES

doc/general.texi

@@ -307,6 +307,7 @@ library:
 @item RTP                       @tab X @tab X
 @item RTSP                      @tab X @tab X
 @item SAP                       @tab X @tab X
+@item SBG                       @tab   @tab X
 @item SDP                       @tab   @tab X
 @item Sega FILM/CPK             @tab   @tab X
     @tab Used in many Sega Saturn console games.

libavformat/Makefile

@@ -281,6 +281,7 @@ OBJS-$(CONFIG_RTSP_MUXER)                += rtsp.o rtspenc.o httpauth.o \
                                             rtpenc_chain.o
 OBJS-$(CONFIG_SAP_DEMUXER)               += sapdec.o
 OBJS-$(CONFIG_SAP_MUXER)                 += sapenc.o rtpenc_chain.o
+OBJS-$(CONFIG_SBG_DEMUXER)               += sbgdec.o
 OBJS-$(CONFIG_SDP_DEMUXER)               += rtsp.o
 OBJS-$(CONFIG_SEGAFILM_DEMUXER)          += segafilm.o
 OBJS-$(CONFIG_SEGMENT_MUXER)          	 += segment.o

libavformat/allformats.c

@@ -201,6 +201,7 @@ void av_register_all(void)
     REGISTER_MUXDEMUX (RTP, rtp);
     REGISTER_MUXDEMUX (RTSP, rtsp);
     REGISTER_MUXDEMUX (SAP, sap);
+    REGISTER_DEMUXER  (SBG, sbg);
     REGISTER_DEMUXER  (SDP, sdp);
 #if CONFIG_RTPDEC
     av_register_rtp_dynamic_payload_handlers();

libavformat/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 53
-#define LIBAVFORMAT_VERSION_MINOR 25
+#define LIBAVFORMAT_VERSION_MINOR 26
 #define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \