ffmpeg command gives error when used in python - bash

Question

When I run this command from the shell it works perfectly.
ffmpeg -nostdin -i /data/binil/v2t_final/output/cnbctv18/2018_07_02_14_38_30/tmp/merged.avi -ss 00:00:00 -vcodec h264 -vf fps=25 -to 00:6:43 /data/binil/v2t_final/output/cnbctv18/2018_07_02_14_38_30/1/1.avi
But the same thing when I do in python it gives error:
import sys
import os
INPUT_DIR = sys.argv[1]
INPUT_VIDEO = sys.argv[2]
OUTPUT_PATH = sys.argv[3]
SOURCE = sys.argv[4]
DATE = sys.argv[5]
INPUT = INPUT_DIR+"sorted_result.txt"
COUNT=1
initial="00:00:00"
with open(INPUT,"r") as f:
for line in f.readlines():
OUT_DIR = OUTPUT_PATH+str(COUNT)
directory = os.path.abspath(OUT_DIR)
print('OUT DIR',OUT_DIR)
print('directory',directory)
try:
os.mkdir(directory)
except:
pass
cmd_1 = "ffmpeg -nostdin -i "+INPUT_VIDEO+" -ss " +initial+ " -vcodec h264 -vf fps=25 -to " +line+ " " +OUT_DIR+"/"+str(COUNT)+".avi"
os.system(cmd_1)
COUNT += 1
initial=line
I cant understand the problem:
The error is as follows:
ffmpeg version 4.0-static https://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc-6 --enable-libxml2 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gray --enable-libaom --enable-libfribidi --enable-libass --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg
libavutil 56. 14.100 / 56. 14.100
libavcodec 58. 18.100 / 58. 18.100
libavformat 58. 12.100 / 58. 12.100
libavdevice 58. 3.100 / 58. 3.100
libavfilter 7. 16.100 / 7. 16.100
libswscale 5. 1.100 / 5. 1.100
libswresample 3. 1.100 / 3. 1.100
libpostproc 55. 1.100 / 55. 1.100
Trailing options were found on the commandline.
Input #0, avi, from '/data/binil/v2t_final/output/cnbctv18/2018_07_02_14_38_30/tmp/merged.avi':
Metadata:
encoder : Lavf58.12.100
Duration: 01:00:50.23, start: 0.000000, bitrate: 1334 kb/s
Stream #0:0: Video: h264 (High) (H264 / 0x34363248), yuv420p(progressive), 512x288 [SAR 1:1 DAR 16:9], 1001 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, fltp, 639 kb/s
At least one output file must be specified
sh: line 1: /data/binil/v2t_final/output/cnbctv18/2018_07_02_14_38_30/1/1.avi: Permission denied
Please help.
This is some dummy text I am writing because it looks like stack overflow does not accept less description and more code. Please don't mind these sentences. I cant believe that I am still writing this and it is still requesting me to add some more description. I am still doing it. Don't know till what extent do I have to write. I hope this much is enough.

Answer 1

Got the error.
The input file contains timestamps each one on a new line so it was taking the '\n' character along with the timestamp in the ffmpeg command. Hence it considered -vcodec as a new command and resulted in error.