mpg123: first go at A-B looping

git-svn-id: svn://scm.orgis.org/mpg123/trunk@5234 35dc7657-300d-0410-a2e5-dc2837fedb53

NEWS

@@ -9,7 +9,10 @@ TODO: fix up position calculations with syn123 resampling, drop 2to1, 4to1 decod
    correct one is included (at least gcc picks the one in the same directory as the
    including header first).
 -- TODO: make headers build-independent (some lfs aliasing for non-sensitive)
-- mpg123: added --libversion
+- mpg123:
+-- Added --libversion.
+-- Added proper A-B looping with terminal control key 'o', renamed
+   --pauseloop to --presetloop.
 - libmpg123, libout123, libsyn123: bumped API version for version query
   functions
 - libout123:

man1/mpg123.1

@@ -412,7 +412,8 @@ Quiet.  Suppress diagnostic messages.
 Enable terminal control keys. This is enabled automatically if a terminal is detected.
 By default use 's' or the space bar to stop/restart (pause, unpause) playback, 'f' to jump forward to the next song, 'b' to jump back to the
 beginning of the song, ',' to rewind, '.' to fast forward, and 'q' to quit.
-Type 'h' for a full list of available controls.
+Type 'h' for a full list of available controls. The A-B loop feature with key 'o' changes the preset loop interval to the interval
+between two presses of 'o', the third press (or 'p') ending the looped playback. The key 'p' will use the updated loop interval after that.
 .TP
 \fB\-\^\-no\-control
 Disable terminal control even if terminal is detected.
@@ -422,8 +423,8 @@ In an xterm, rxvt, screen, iris-ansi (compatible, TERM environment variable is e
 playing.
 .TP
 \fB\-\^\-pauseloop \fIseconds
-Set the length of the loop interval in terminal control paused mode, away from the default of 0.5 seconds, as a floating
-point number.
+Set the length of the loop interval in terminal control fixed looping mode, away from the default of 0.5 seconds, as a floating
+point number. This value can be overwritten at runtime using the A-B loop feature.
 .TP
 \fB\-\^\-name \fIname
 Set the name of this instance, possibly used in various places. This sets the client name for JACK output.

src/common.c

@@ -20,8 +20,8 @@
 
 #include "debug.h"
 
-int stopped = 0;
-int paused = 0;
+enum player_state playstate = STATE_PLAYING;
+const char playsym[STATE_COUNT] = { '>', '_', '=', '?' };
 int muted = 0;
 
 const char* rva_name[3] = { "off", "mix", "album" };
@@ -222,7 +222,7 @@ void print_stat(mpg123_handle *fr, long offset, out123_handle *ao, int draw_bar
 	   Buffering makes the relationships between the numbers non-trivial. */
 	rframes = frames-frame;
 	// May be negative, a countdown. Buffer only confuses in paused (looping) mode, though.
-	elapsed = decoded + offset*spf - (paused ? 0 : buffered);
+	elapsed = decoded + offset*spf - (playstate==STATE_LOOPING ? 0 : buffered);
 	remain  = elapsed > 0 ? length - elapsed : length;
 	if(  MPG123_OK == mpg123_info(fr, &mi)
 	  && MPG123_OK == mpg123_getvolume(fr, &basevol, &realvol, NULL) )
@@ -285,7 +285,7 @@ void print_stat(mpg123_handle *fr, long offset, out123_handle *ao, int draw_bar
 		/* Start with position info. */
 		len = snprintf( line, linelen
 		,	"%c %s+%s %c%02lu:%02lu%c%02lu+%02lu:%02lu%c%02lu"
-		,	stopped ? '_' : (paused ? '=' : '>')
+		,	playsym[playstate]
 		,	framestr[0], framestr[1]
 		,	sign[0]
 		,	times[0][0], times[0][1], timesep[0], times[0][2]

src/common.h

@@ -1,7 +1,7 @@
 /*
 	common: anything can happen here... frame reading, output, messages
 
-	copyright ?-2020 by the mpg123 project - free software under the terms of the LGPL 2.1
+	copyright ?-2022 by the mpg123 project - free software under the terms of the LGPL 2.1
 	see COPYING and AUTHORS files in distribution or http://mpg123.org
 	initially written by Michael Hipp
 */
@@ -12,8 +12,13 @@
 #include "mpg123app.h"
 #include "out123.h"
 
-extern int stopped;
-extern int paused;
+enum player_state
+{
+	STATE_PLAYING=0
+,	STATE_STOPPED, STATE_LOOPING, STATE_AB
+,	STATE_COUNT
+};
+extern enum player_state playstate;
 extern int muted;
 
 void print_header(mpg123_handle *);

src/mpg123.c

@@ -723,6 +723,7 @@ topt opts[] = {
 	{0, "resync-limit", GLO_ARG | GLO_LONG, 0, &param.resync_limit, 0},
 	{0, "pitch", GLO_ARG|GLO_DOUBLE, 0, &param.pitch, 0},
 	{0, "pauseloop", GLO_ARG|GLO_DOUBLE, 0, &param.pauseloop, 0},
+	{0, "presetloop", GLO_ARG|GLO_DOUBLE, 0, &param.pauseloop, 0},
 #ifdef NETWORK
 	{0, "ignore-mime", GLO_LONG, set_appflag, &appflag, MPG123APP_IGNORE_MIME },
 #endif
@@ -1343,6 +1344,7 @@ int main(int sys_argc, char ** sys_argv)
 #endif
 		}
 		if(!APPFLAG(MPG123APP_CONTINUE)) frames_left = param.frame_number;
+		term_new_track();
 
 		debug1("Going to play %s", strcmp(fname, "-") ? fname : "standard input");
 		// If a previous track did not cause error, we forget the success to
@@ -1720,7 +1722,7 @@ static void long_usage(int err)
 	#ifndef GENERIC
 	fprintf(o,"        --title            set terminal title to filename\n");
 	#endif
-	fprintf(o,"        --pauseloop <s>    loop interval in (fractional) seconds\n");
+	fprintf(o,"        --presetloop <s>   preset loop interval in (fractional) seconds\n");
 	fprintf(o,"        --name <n>         set instance name (used in various places)\n");
 	fprintf(o,"        --long-tag         spacy id3 display with every item on a separate line\n");
 	fprintf(o,"        --lyrics           show lyrics (from ID3v2 USLT frame)\n");

src/term.c

@@ -18,7 +18,7 @@
 
 static int term_enable = 0;
 static const char *extrabreak = "";
-int seeking = FALSE;
+static int seeking = FALSE;
 
 extern out123_handle *ao;
 
@@ -36,7 +36,8 @@ struct keydef term_help[] =
 	,{ MPG123_NEXT_DIR_KEY, 0, "next directory" }
 	,{ MPG123_PREV_DIR_KEY, 0, "previous directory" }
 	,{ MPG123_BACK_KEY,    0, "back to beginning" }
-	,{ MPG123_PAUSE_KEY,   0, "loop (--pauseloop)" }
+	,{ MPG123_LOOP_KEY,    0, "A-B loop" }
+	,{ MPG123_PAUSE_KEY,   0, "preset loop" }
 	,{ MPG123_FORWARD_KEY, 0, "forward" }
 	,{ MPG123_REWIND_KEY,  0, "rewind" }
 	,{ MPG123_FAST_FORWARD_KEY, 0, "fast forward" }
@@ -104,7 +105,11 @@ void term_hint(void)
 
 static void term_handle_input(mpg123_handle *, out123_handle *, int);
 
-static int pause_cycle;
+// A-B looping sets pause_cycle at runtime baseon the difference to
+// pause_begin. Keeping the broken wording for 'pause' for now. To the
+// outside world, it is 'looping'.
+static double pause_begin = -1;
+static off_t pause_cycle;
 
 static int print_index(mpg123_handle *mh)
 {
@@ -129,28 +134,27 @@ static int print_index(mpg123_handle *mh)
 
 static off_t offset = 0;
 
+void term_new_track(void)
+{
+	pause_begin = -1;
+}
+
 /* Go back to the start for the cyclic pausing. */
 void pause_recycle(mpg123_handle *fr)
 {
 	/* Take care not to go backwards in time in steps of 1 frame
 		 That is what the +1 is for. */
-	pause_cycle=(int)(param.pauseloop/mpg123_tpf(fr));
+	pause_cycle=(off_t)(param.pauseloop/mpg123_tpf(fr));
 	offset-=pause_cycle;
 }
 
-/* Done with pausing, no offset anymore. Just continuous playback from now. */
-void pause_uncycle(void)
-{
-	offset += pause_cycle;
-}
-
 off_t term_control(mpg123_handle *fr, out123_handle *ao)
 {
 	offset = 0;
-	debug2("control for frame: %li, enable: %i", (long)mpg123_tellframe(fr), term_enable);
+	debug2("control for frame: %"OFF_P", enable: %i", (off_p)mpg123_tellframe(fr), term_enable);
 	if(!term_enable) return 0;
 
-	if(paused)
+	if(playstate==STATE_LOOPING)
 	{
 		/* pause_cycle counts the remaining frames _after_ this one, thus <0, not ==0 . */
 		if(--pause_cycle < 0)
@@ -164,14 +168,14 @@ off_t term_control(mpg123_handle *fr, out123_handle *ao)
 		if((offset < 0) && (-offset > framenum)) offset = - framenum;
 		if(param.verbose && offset != old_offset)
 			print_stat(fr,offset,ao,1,&param);
-	} while (!intflag && stopped);
+	} while (!intflag && playstate==STATE_STOPPED);
 
 	/* Make the seeking experience with buffer less annoying.
 	   No sound during seek, but at least it is possible to go backwards. */
 	if(offset)
 	{
 		if((offset = mpg123_seek_frame(fr, offset, SEEK_CUR)) >= 0)
-		debug1("seeked to %li", (long)offset);
+		debug1("seeked to %"OFF_P, (off_p)offset);
 		else error1("seek failed: %s!", mpg123_strerror(fr));
 		/* Buffer resync already happened on un-stop? */
 		/* if(param.usebuffer) audio_drop(ao);*/
@@ -182,14 +186,14 @@ off_t term_control(mpg123_handle *fr, out123_handle *ao)
 /* Stop playback while seeking if buffer is involved. */
 static void seekmode(mpg123_handle *mh, out123_handle *ao)
 {
-	if(param.usebuffer && !stopped)
+	if(param.usebuffer && playstate!=STATE_STOPPED)
 	{
 		int channels = 0;
 		int encoding = 0;
 		int pcmframe;
 		off_t back_samples = 0;
 
-		stopped = TRUE;
+		playstate = STATE_STOPPED;
 		out123_pause(ao);
 		if(param.verbose)
 			print_stat(mh, 0, ao, 0, &param);
@@ -233,7 +237,9 @@ static void term_handle_key(mpg123_handle *fr, out123_handle *ao, char val)
 	case MPG123_BACK_KEY:
 		out123_pause(ao);
 		out123_drop(ao);
-		if(paused) pause_cycle=(int)(param.pauseloop/mpg123_tpf(fr));
+		// Revisit: What does that really achieve?
+		if(playstate==STATE_LOOPING)
+			pause_cycle=(int)(param.pauseloop/mpg123_tpf(fr));
 
 		if(mpg123_seek_frame(fr, 0, SEEK_SET) < 0)
 		error1("Seek to begin failed: %s", mpg123_strerror(fr));
@@ -252,24 +258,61 @@ static void term_handle_key(mpg123_handle *fr, out123_handle *ao, char val)
 	break;
 	case MPG123_QUIT_KEY:
 		debug("QUIT");
-		if(stopped)
+		if(playstate==STATE_STOPPED)
 		{
 			if(param.verbose)
 				print_stat(fr,0,ao,0,&param);
 
-			stopped = 0;
+			playstate=STATE_PLAYING; // really necessary/sensible?
 			out123_pause(ao); /* no chance for annoying underrun warnings */
 			out123_drop(ao);
 		}
 		set_intflag();
 		offset = 0;
 	break;
+	case MPG123_LOOP_KEY:
+	// In paused (looping) state, the loop key ends the loop just like the other one.
+	// Otherwise, it starts playback and enters A-? mode. If in A-? mode, it
+	// sets the loop interval and then again falls through.
+	if(playstate != STATE_LOOPING)
+	{
+		playstate = STATE_AB;
+		// Careful with positioning, output might have 
+		long outrate = 0;
+		int outframesize = 0;
+		long inrate = 0;
+		if(out123_getformat(ao, &outrate, NULL, NULL, &outframesize) || outrate==0)
+			break;
+		if(mpg123_getformat(fr, &inrate, NULL, NULL) || inrate==0)
+			break;
+
+		double position = (double)mpg123_tell(fr)/inrate + (double)out123_buffered(ao)/(outrate * outframesize);
+		if(pause_begin < 0)
+		{
+			pause_begin = position;
+			if(param.verbose)
+				print_stat(fr, 0, ao, 1, &param);
+			else
+				fprintf(stderr, "%s", MPG123_AB_STRING);
+			break;
+		} else if(position <= pause_begin)
+		{
+			// Pathological situation: You seeked around, whatever. No loop.
+			playstate=STATE_LOOPING; // Let fall-through fix up things.
+		}
+		{
+			param.pauseloop = (position > pause_begin) ? (position-pause_begin) : mpg123_tpf(fr);
+			// Fall throuth to start looping.
+		}
+	}
 	case MPG123_PAUSE_KEY:
-		paused=1-paused;
+	{
+		playstate = playstate == STATE_LOOPING ? STATE_PLAYING : STATE_LOOPING;
+		pause_begin = -1;
 		size_t buffered = out123_buffered(ao);
 		out123_pause(ao); /* underrun awareness */
 		out123_drop(ao);
-		if(paused)
+		if(playstate == STATE_LOOPING)
 		{
 			// Make output buffer react immediately, dropping decoded audio
 			// and (at least trying to) seeking back in input.
@@ -287,23 +330,20 @@ static void term_handle_key(mpg123_handle *fr, out123_handle *ao, char val)
 		}
 		else
 			out123_param_float(ao, OUT123_PRELOAD, param.preload);
-		if(stopped)
-			stopped=0;
 		if(param.verbose)
 			print_stat(fr, 0, ao, 1, &param);
 		else
-			fprintf(stderr, "%s", (paused) ? MPG123_PAUSED_STRING : MPG123_EMPTY_STRING);
+			fprintf(stderr, "%s", (playstate == STATE_LOOPING) ? MPG123_PAUSED_STRING : MPG123_EMPTY_STRING);
+	}
 	break;
 	case MPG123_STOP_KEY:
 	case ' ':
 		/* TODO: Verify/ensure that there is no "chirp from the past" when
 		   seeking while stopped. */
-		stopped=1-stopped;
-		if(paused) {
-			paused=0;
+		if(playstate == STATE_LOOPING)
 			offset -= pause_cycle;
-		}
-		if(stopped)
+		playstate = playstate == STATE_STOPPED ? STATE_PLAYING : STATE_STOPPED;
+		if(playstate == STATE_STOPPED)
 			out123_pause(ao);
 		else
 		{
@@ -314,7 +354,7 @@ static void term_handle_key(mpg123_handle *fr, out123_handle *ao, char val)
 		if(param.verbose)
 			print_stat(fr, 0, ao, 1, &param);
 		else
-			fprintf(stderr, "%s", (stopped) ? MPG123_STOPPED_STRING : MPG123_EMPTY_STRING);
+			fprintf(stderr, "%s", (playstate==STATE_STOPPED) ? MPG123_STOPPED_STRING : MPG123_EMPTY_STRING);
 	break;
 	case MPG123_FINE_REWIND_KEY:
 		seekmode(fr, ao);
@@ -547,7 +587,7 @@ static void term_handle_input(mpg123_handle *fr, out123_handle *ao, int do_delay
 {
 	char val;
 	/* Do we really want that while loop? This means possibly handling multiple inputs that come very rapidly in one go. */
-	while(term_get_key(stopped, do_delay, &val))
+	while(term_get_key(playstate==STATE_STOPPED, do_delay, &val))
 	{
 		term_handle_key(fr, ao, val);
 	}

src/term.h

@@ -21,6 +21,7 @@
 #define MPG123_BACK_KEY	'b'
 #define MPG123_NEXT_KEY	'f'
 #define MPG123_PAUSE_KEY	'p'
+#define MPG123_LOOP_KEY	'o'
 #define MPG123_QUIT_KEY	'q'
 /* space bar is alias for that */
 #define MPG123_STOP_KEY	's'
@@ -76,8 +77,9 @@
 #define MPG123_PITCH_VAL 0.001
 #define MPG123_PITCH_BVAL 0.01
 
-#define MPG123_PAUSED_STRING	"Paused. \b\b\b\b\b\b\b\b"
+#define MPG123_PAUSED_STRING	"Looping.\b\b\b\b\b\b\b\b"
 #define MPG123_STOPPED_STRING	"Stopped.\b\b\b\b\b\b\b\b"
+#define MPG123_AB_STRING		"Loop A-?\b\b\b\b\b\b\b\b"
 #define MPG123_EMPTY_STRING	"        \b\b\b\b\b\b\b\b"
 
 /* Need it as string for the param struct, change according to the above. */
@@ -87,6 +89,7 @@
 
 int term_init(void); // -1 on error, 0 success or no terminal desired
 void term_exit(void);
+void term_new_track(void); // prepare for a new track being played
 off_t term_control(mpg123_handle *mh, out123_handle *ao);
 void term_hint(void); /* Print a message hinting at terminal usage. */