Getting timecode location for memory locations

[evanmang]

Hi! I'm trying to return the timecode of the memory locations from a session and having some issues (i assume i'm doing some bad math somewhere....) Is there an easier way to do this? Pulling the data from AppleScript on large sessions is SUPER slow, and this pulls the memory location list super fast even on very large sessions, but my timecodes get off by a few frames.

My script is below: forgive my code, i'm a sound designer, not a programmer ;)

#list memory locations
import sys
import datetime
import math

from ptsl import open_engine
from ptsl import PTSL_pb2 as pt

delimiter='###'

#Convert Session start time to total number of frames
def timecode_to_frames(timecode, frame_rate):
    tc = timecode.split(":",4)
    tc_hour = int(tc[0])
    tc_min = int(tc[1])
    tc_sec = int(tc[2])
    tc_frame = (tc[3])
#remove decimal and significant digits from frame field
    tc_frame = int(tc_frame[:-3])
    frame_count = int((tc_hour*3600*frame_rate)+(tc_min*60*frame_rate)+(tc_sec*frame_rate)+tc_frame)
    return frame_count
    
#Convert number of frames to timecode
def frames_to_timecode(result_frames, frame_rate):
    total_seconds = result_frames / frame_rate
    hours = int(total_seconds // 3600)
    total_seconds %= 3600
    minutes = int(total_seconds // 60)
    seconds = int(total_seconds % 60)
    frames = int(result_frames % frame_rate)
    return f"{hours:02d}:{minutes:02d}:{seconds:02d}:{frames:02d}"


def samples_to_timecode(samples, sample_rate):
    #Convert PTSL framerate for calculation
    if pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps23976':
        frame_rate = 23.976
    elif pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps24':
        frame_rate = 24    
    elif pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps30':
        frame_rate = 30
    elif pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps2997':
        frame_rate = 29.97
    elif pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps60':
        frame_rate = 60
    elif pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()) == 'STCR_Fps5994':
        frame_rate = 60
    else:
        raise ValueError("Unsupported frame rate") 
    
    #get location in frames from session start
    samples = int(samples)        
    samples_per_frame = round(sample_rate / frame_rate)
    total_frames = int(samples // samples_per_frame)

    #get total number of frames of session start time + memory location
    start_frames = timecode_to_frames(engine.session_start_time(), frame_rate)
    result_frames = (total_frames + start_frames)
    
    return_frames = frames_to_timecode(result_frames, frame_rate)
    return(return_frames)

with open_engine(company_name="py-ptsl",
                 application_name=sys.argv[0]) as engine:

    #print("Session Timecode Rate: %s" % pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()))
    #print("Session Sample Rate: %i" % engine.session_sample_rate())
    #print("Session Start Time: %s" % engine.session_start_time())
    #ptslFR = pt.SessionTimeCodeRate.Name(engine.session_timecode_rate())
    print("Marker List:")


    marker_list = engine.get_memory_locations()
    
    for marker in marker_list:
        mode = list("   ")
        timecode = samples_to_timecode(marker.start_time, engine.session_sample_rate())
        #print(marker)
        print(marker.number,delimiter,marker.name,delimiter,timecode)

[evanmang]

Here's what i'm returning vs: what the timecodes are in the session:

[iluvcapra]

In frames_to_timecode, you have this line:

frames = int(result_frames % frame_rate)

When frame_rate is non-integral this might not be doing what you want. Usually you have to handle timecode rates as Rationals, so like instead of 23.976 you use a Rational(24000,1001) and handle the remainders.

[evanmang]

Thanks for the tip @iluvcapra.

I actually realized that since all i'm doing is counting frames, my error was actually using the real frame-rate, rather than the full integer equivalent, since there are 24 frames per second as far as timecode goes, it's just not a "real" second.

So all i needed to do was set my calculation framerate to 24 if 23.976 etc... and now it seems it's working.

[StephenMachete]

I personally use this Library for timecode stuff. Here is a new version of your code using it. I can't test it right now, but i think it should work.

#list memory locations
import sys

from ptsl import open_engine
from ptsl import PTSL_pb2 as pt

delimiter='###'

def samples_to_timecode(samples, sample_rate):
    # split string reponse at "Fps" and use second half to get "23976"
    frame_rate = pt.SessionTimeCodeRate.Name(engine.session_timecode_rate()).split("Fps")[1]
    # insert dot into string if needed
    if len(frame_rate) > 2:
        frame_rate = frame_rate[:2] + "." + frame_rate[2:]
    frames = round(int(samples) / (sample_rate / float(frame_rate)))
    # pip install timecode || https://github.com/eoyilmaz/timecode
    from timecode import Timecode
    tc = Timecode(framerate=frame_rate, frames=frames)
    return(tc)


with open_engine(company_name="py-ptsl",
                 application_name=sys.argv[0]) as engine:
    print("Marker List:")

    marker_list = engine.get_memory_locations()
    
    for marker in marker_list:
        mode = list("   ")
        timecode = samples_to_timecode(marker.start_time, engine.session_sample_rate())
        print(marker.number,delimiter,marker.name,delimiter,timecode)

[evanmang]

thanks! I'll check this out.