gstreamer/ext/dv/gstsmptetimecode.c

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/* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, 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;
}