How to make TIME subtitles(.srt, .smi etc) with frame unit - python-3.x

Question

I want to create a Python script that make subtitle (a ticking timecode).
I have an h.264 binary file that has timestamp in each frame. so I want to parse this timestamp and make the subtitle with it.
Here's what I've tried with ffmpeg below.
ffmpeg -y -i video.avi -vf "drawtext=fontfile=C:\Windows\Fonts\consolab.ttf: fontsize=12:fontcolor=yellow: box=1:boxcolor=black#0.4: text='TIME\: %{pts\:gmtime\:1561939200}':x=(w-tw)/2:y=(h-th)/2" test.avi
Output .avi is okay with the timestamp, but, I needed to re-encode the source video file which takes a lot of time.
So, I want to use a different way, which is creating subtitles.
Question is, is there any way to make subtitle with frame time? or useful info to fill me in?
The current result:
The expected result:

Answer 1

You can use directly Timecode by defining the starting time :
ffmpeg -i source_file -c:v libx264 -vf drawtext="fontfile=C\\:/Windows/Fonts/arial.ttf:fontsize=45:timecode='10\:00\:00\:00':fontcolor='white':box=1:boxcolor='black':rate=25:x=(w-text_w)/2:y=h/1.2" -c:a aac -f mp4 output_with_TC.mp4
You can also grab timecode from file using ffprobe and use it in a batch file
#echo off
cd C:\bin
set file=%1
For %%A in ("%file%") do (
Set Folder=%%~dpA
Set Name=%%~nA
)
set "CommandLine=ffprobe -i %file% -show_entries format_tags=timecode -of default=noprint_wrappers=1"
setlocal EnableDelayedExpansion
for /F "delims=" %%I in ('!CommandLine!') do set "TC=%%I"
echo.File is: %file%
echo.TC is: %TC%
set hours=%TC:~13,2%
set minutes=%TC:~16,2%
set seconds=%TC:~19,2%
set frames=%TC:~22,2%
set h=!hours: =!
set m=!minutes: =!
set s=!seconds: =!
set f=!frames: =!
set final_TC=%h%:%m%:%s%:%f%
echo.final_TC is : %final_TC%
ffmpeg -i %file% -c:v libx264 -vf drawtext="fontfile=C\\:/Windows/Fonts/arial.ttf:fontsize=45:timecode=\'%final_TC%\':fontcolor='white':box=1:boxcolor='black#0.4':rate=25:x=1600:y=30" -c:a aac -f mp4 output_%Name%.mp4 -y
endlocal

Answer 2

Maybe this code will help you to get a quick solution (I've modified slightly for posting here):
Set the fps variable to your own video's FPS.
set the myTimeNum var by using a timer to increase some frameNum count every FPS interval.
Logic:
Where example FPS is 10...
FPS= 10; frameNum = 0; myTimeNum = 0
Means for 10 times per second (using a timer) you must...
myTimeNum = (1000 / FPS) * frameNum
timecode = smpte.totc(myTimeNum, fps)
frameNum++
Code to try:
fps = 30
myTimeNum = 50000;
timecode = smpte.totc(myTimeNum, fps)
print timecode
#Converts frames to SMPTE timecode of arbitrary frame rate and back.
#For DF calculations use 29.976 frame rate.
#Igor Ridanovic, igor#HDhead.com
def totc(x, fps):
"""Converts frame count to SMPTE timecode."""
spacer = ':'
frHour = fps * 3600
frSec = fps * 60
hr = int(x // frHour)
mn = int((x - hr * frHour) // frSec)
sc = int((x - hr * frHour - mn * frSec) // fps)
fr = int(round(x - hr * frHour - mn * frSec - sc * fps))
return(
str(hr).zfill(2) + spacer +
str(mn).zfill(2) + spacer +
str(sc).zfill(2) + spacer +
str(fr).zfill(2))