dvdemux: Add code to parse SMPTE time codes

Code to convert time codes to/from timestamps and frame numbers.

ext/dv/Makefile.am

@@ -11,3 +11,10 @@ libgstdv_la_LIBTOOLFLAGS = --tag=disable-static
 noinst_HEADERS = gstdvdemux.h gstdvdec.h
 
 EXTRA_DIST = NOTES
+
+noinst_PROGRAMS = smpte_test
+
+smpte_test_SOURCES = smpte_test.c gstsmptetimecode.c
+smpte_test_CFLAGS = $(GST_PLUGINS_BASE_CFLAGS) $(GST_CFLAGS) $(LIBDV_CFLAGS)
+smpte_test_LDADD = $(GST_BASE_LIBS) $(GST_LIBS)
+

ext/dv/gstsmptetimecode.c

@@ -0,0 +1,240 @@
+/* GStreamer
+ * Copyright (C) 2009 David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/*
+ * Utility functions for handing SMPTE Time Codes, as described in
+ * SMPTE Standard 12M-1999.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gstsmptetimecode.h"
+
+#define NTSC_FRAMES_PER_10_MINS (10*60*30 - 10*2 + 2)
+#define NTSC_FRAMES_PER_HOUR (6*NTSC_FRAMES_PER_10_MINS)
+
+/**
+ * gst_smpte_time_code_from_frame_number:
+ * @system: SMPTE Time Code system
+ * @time_code: pointer to time code structure
+ * @frame_number: integer frame number
+ *
+ * Converts a frame number to a time code.
+ *
+ * Returns: TRUE if the conversion was successful
+ */
+gboolean
+gst_smpte_time_code_from_frame_number (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode * time_code, int frame_number)
+{
+  int ten_mins;
+  int n;
+
+  g_return_val_if_fail (time_code != NULL, FALSE);
+  g_return_val_if_fail (GST_SMPTE_TIME_CODE_SYSTEM_IS_VALID (system), FALSE);
+
+  time_code->hours = 99;
+  time_code->minutes = 99;
+  time_code->seconds = 99;
+  time_code->frames = 99;
+
+  if (frame_number < 0)
+    return FALSE;
+
+  switch (system) {
+    case GST_SMPTE_TIME_CODE_SYSTEM_30:
+      if (frame_number >= 24 * NTSC_FRAMES_PER_HOUR)
+        return FALSE;
+
+      ten_mins = frame_number / NTSC_FRAMES_PER_10_MINS;
+      frame_number -= ten_mins * NTSC_FRAMES_PER_10_MINS;
+
+      time_code->hours = ten_mins / 6;
+      time_code->minutes = 10 * (ten_mins % 6);
+
+      if (frame_number < 2) {
+        /* treat the first two frames of each ten minutes specially */
+        time_code->seconds = 0;
+        time_code->frames = frame_number;
+      } else {
+        n = (frame_number - 2) / (60 * 30 - 2);
+        time_code->minutes += n;
+        frame_number -= n * (60 * 30 - 2);
+
+        time_code->seconds = frame_number / 30;
+        time_code->frames = frame_number % 30;
+      }
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_25:
+      if (frame_number >= 24 * 60 * 60 * 25)
+        return FALSE;
+
+      time_code->frames = frame_number % 25;
+      frame_number /= 25;
+      time_code->seconds = frame_number % 60;
+      frame_number /= 60;
+      time_code->minutes = frame_number % 60;
+      frame_number /= 60;
+      time_code->hours = frame_number;
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_24:
+      if (frame_number >= 24 * 60 * 60 * 24)
+        return FALSE;
+
+      time_code->frames = frame_number % 24;
+      frame_number /= 24;
+      time_code->seconds = frame_number % 60;
+      frame_number /= 60;
+      time_code->minutes = frame_number % 60;
+      frame_number /= 60;
+      time_code->hours = frame_number;
+      break;
+  }
+
+  return TRUE;
+}
+
+/**
+ * gst_smpte_time_code_is_valid:
+ * @system: SMPTE Time Code system
+ * @time_code: pointer to time code structure
+ *
+ * Checks that the time code represents a valid time code.
+ *
+ * Returns: TRUE if the time code is valid
+ */
+gboolean
+gst_smpte_time_code_is_valid (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode * time_code)
+{
+  g_return_val_if_fail (time_code != NULL, FALSE);
+  g_return_val_if_fail (GST_SMPTE_TIME_CODE_SYSTEM_IS_VALID (system), FALSE);
+
+  if (time_code->hours < 0 || time_code->hours >= 24)
+    return FALSE;
+  if (time_code->minutes < 0 || time_code->minutes >= 60)
+    return FALSE;
+  if (time_code->seconds < 0 || time_code->seconds >= 60)
+    return FALSE;
+  if (time_code->frames < 0)
+    return FALSE;
+
+  switch (system) {
+    case GST_SMPTE_TIME_CODE_SYSTEM_30:
+      if (time_code->frames >= 30)
+        return FALSE;
+      if (time_code->frames >= 2 || time_code->seconds > 0)
+        return TRUE;
+      if (time_code->minutes % 10 != 0)
+        return FALSE;
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_25:
+      if (time_code->frames >= 25)
+        return FALSE;
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_24:
+      if (time_code->frames >= 24)
+        return FALSE;
+      break;
+  }
+  return TRUE;
+}
+
+/**
+ * gst_smpte_time_get_frame_number:
+ * @system: SMPTE Time Code system
+ * @frame_number: pointer to frame number
+ * @time_code: pointer to time code structure
+ *
+ * Converts the time code structure to a linear frame number.
+ *
+ * Returns: TRUE if the time code could be converted
+ */
+gboolean
+gst_smpte_time_code_get_frame_number (GstSMPTETimeCodeSystem system,
+    int *frame_number, GstSMPTETimeCode * time_code)
+{
+  int frame = 0;
+
+  g_return_val_if_fail (GST_SMPTE_TIME_CODE_SYSTEM_IS_VALID (system), FALSE);
+  g_return_val_if_fail (time_code != NULL, FALSE);
+
+  if (!gst_smpte_time_code_is_valid (system, time_code)) {
+    return FALSE;
+  }
+
+  switch (system) {
+    case GST_SMPTE_TIME_CODE_SYSTEM_30:
+      frame = time_code->hours * NTSC_FRAMES_PER_HOUR;
+      frame += (time_code->minutes / 10) * NTSC_FRAMES_PER_10_MINS;
+      frame += (time_code->minutes % 10) * (30 * 60 - 2);
+      frame += time_code->seconds * 30;
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_25:
+      time_code->frames =
+          25 * ((time_code->hours * 60 + time_code->minutes) * 60 +
+          time_code->seconds);
+      break;
+    case GST_SMPTE_TIME_CODE_SYSTEM_24:
+      time_code->frames =
+          24 * ((time_code->hours * 60 + time_code->minutes) * 60 +
+          time_code->seconds);
+      break;
+  }
+  frame += time_code->frames;
+
+  if (frame_number) {
+    *frame_number = frame;
+  }
+
+  return TRUE;
+}
+
+/**
+ * gst_smpte_time_get_timestamp:
+ * @system: SMPTE Time Code system
+ * @time_code: pointer to time code structure
+ *
+ * Converts the time code structure to a timestamp.
+ *
+ * Returns: Time stamp for time code, or GST_CLOCK_TIME_NONE if time
+ *   code is invalid.
+ */
+GstClockTime
+gst_smpte_time_code_get_timestamp (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode * time_code)
+{
+  int frame_number;
+
+  g_return_val_if_fail (GST_SMPTE_TIME_CODE_SYSTEM_IS_VALID (system),
+      GST_CLOCK_TIME_NONE);
+  g_return_val_if_fail (time_code != NULL, GST_CLOCK_TIME_NONE);
+
+  if (gst_smpte_time_code_get_frame_number (system, &frame_number, time_code)) {
+    static int framerate_n[3] = { 3000, 25, 24 };
+    static int framerate_d[3] = { 1001, 1, 1 };
+
+    return gst_util_uint64_scale (frame_number,
+        GST_SECOND * framerate_d[system], framerate_n[system]);
+  }
+
+  return GST_CLOCK_TIME_NONE;
+}

ext/dv/gstsmptetimecode.h

@@ -0,0 +1,65 @@
+/* GStreamer
+ * Copyright (C) 2009 David A. Schleef <ds@schleef.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _GST_SMPTE_TIME_CODE_H_
+#define _GST_SMPTE_TIME_CODE_H_
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+typedef struct _GstSMPTETimeCode GstSMPTETimeCode;
+
+/**
+ * GstSMPTETimeCode:
+ * @GST_SMPTE_TIME_CODE_SYSTEM_30: 29.97 frame per second system (NTSC)
+ * @GST_SMPTE_TIME_CODE_SYSTEM_25: 25 frame per second system (PAL)
+ * @GST_SMPTE_TIME_CODE_SYSTEM_24: 24 frame per second system
+ *
+ * Enum value representing SMPTE Time Code system.
+ */
+typedef enum {
+  GST_SMPTE_TIME_CODE_SYSTEM_30 = 0,
+  GST_SMPTE_TIME_CODE_SYSTEM_25,
+  GST_SMPTE_TIME_CODE_SYSTEM_24
+} GstSMPTETimeCodeSystem;
+
+struct _GstSMPTETimeCode {
+  int hours;
+  int minutes;
+  int seconds;
+  int frames;
+};
+
+#define GST_SMPTE_TIME_CODE_SYSTEM_IS_VALID(x) \
+  ((x) >= GST_SMPTE_TIME_CODE_SYSTEM_30 && (x) <= GST_SMPTE_TIME_CODE_SYSTEM_24)
+
+gboolean gst_smpte_time_code_is_valid (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode *time_code);
+gboolean gst_smpte_time_code_from_frame_number (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode *time_code, int frame_number);
+gboolean gst_smpte_time_code_get_frame_number (GstSMPTETimeCodeSystem system,
+    int *frame_number, GstSMPTETimeCode *time_code);
+GstClockTime gst_smpte_time_code_get_timestamp (GstSMPTETimeCodeSystem system,
+    GstSMPTETimeCode *time_code);
+
+G_END_DECLS
+
+#endif
+

ext/dv/smpte_test.c

@@ -0,0 +1,81 @@
+
+#include "config.h"
+
+#include "gstsmptetimecode.h"
+
+#include <glib.h>
+
+#define NTSC_FRAMES_PER_10_MINS (10*60*30 - 10*2 + 2)
+#define NTSC_FRAMES_PER_HOUR (6*NTSC_FRAMES_PER_10_MINS)
+
+
+int
+main (int argc, char *argv[])
+{
+  GstSMPTETimeCode tc;
+  int i;
+  int min;
+
+  for (min = 0; min < 3; min++) {
+    g_print ("--- minute %d ---\n", min);
+    for (i = min * 60 * 30 - 5; i <= min * 60 * 30 + 5; i++) {
+      gst_smpte_time_code_from_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30, &tc,
+          i);
+      g_print ("%d %02d:%02d:%02d:%02d\n", i, tc.hours, tc.minutes, tc.seconds,
+          tc.frames);
+    }
+  }
+
+  for (min = 9; min < 12; min++) {
+    g_print ("--- minute %d ---\n", min);
+    for (i = min * 60 * 30 - 5 - 18; i <= min * 60 * 30 + 5 - 18; i++) {
+      gst_smpte_time_code_from_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30, &tc,
+          i);
+      g_print ("%d %02d:%02d:%02d:%02d\n", i, tc.hours, tc.minutes, tc.seconds,
+          tc.frames);
+    }
+  }
+
+  for (min = -1; min < 2; min++) {
+    int offset = NTSC_FRAMES_PER_HOUR;
+
+    g_print ("--- minute %d ---\n", min);
+    for (i = offset + min * 60 * 30 - 5; i <= offset + min * 60 * 30 + 5; i++) {
+      gst_smpte_time_code_from_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30, &tc,
+          i);
+      g_print ("%d %02d:%02d:%02d:%02d\n", i, tc.hours, tc.minutes, tc.seconds,
+          tc.frames);
+    }
+  }
+
+  for (min = 0; min < 1; min++) {
+    int offset = NTSC_FRAMES_PER_HOUR;
+
+    g_print ("--- minute %d ---\n", min);
+    for (i = 24 * offset - 5; i <= 24 * offset + 5; i++) {
+      gst_smpte_time_code_from_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30, &tc,
+          i);
+      g_print ("%d %02d:%02d:%02d:%02d\n", i, tc.hours, tc.minutes, tc.seconds,
+          tc.frames);
+    }
+  }
+
+  for (i = 0; i < 24 * NTSC_FRAMES_PER_HOUR; i++) {
+    int fn;
+    int ret;
+
+    gst_smpte_time_code_from_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30, &tc,
+        i);
+
+    ret = gst_smpte_time_code_get_frame_number (GST_SMPTE_TIME_CODE_SYSTEM_30,
+        &fn, &tc);
+    if (!ret) {
+      g_print ("bad valid at %d\n", i);
+    }
+    if (fn != i) {
+      g_print ("index mismatch %d != %d\n", fn, i);
+    }
+  }
+
+  return 0;
+}