The given file had a binary value every second, which can be converted to ascii characters which gives the flag. This can be done using tesseract. But I decided to do it manually ?.
I used ffmpeg to split the video into frames using: `ffmpeg.exe -ss 00:00:00 -t 00:00:00 -i flag.avi -qscale:v 2 -r 1 output_image-%3d.jpg`

```
01101110 00110000 00110000 01100010 01111010 01111011 00110111 01101000
00110001 01110011 01011111 00110001 01110011 01011111 00110100 01011111
01110110 00110011 01110010 01111001 01011111 01101100 00110000 01101110
01100111 01011111 01100110 01101100 00110100 01100111 01011111 01110011
00110000 01011111 01110100 01101000 00110100 01110100 01011111 01111001
00110000 01110101 01011111 01100011 00110100 01101110 01101110 00110000
01110100 01011111 01110011 00110000 01101100 01110110 00110011 01011111
00110111 01101000 00110011 01011111 01100011 01101000 00110100 01101100
01101100 00110011 01101110 01100111 00110011 01011111 01101101 00110100
01101110 01110101 00110100 01101100 01101100 01111001 01011111 01100010
00110111 01110111 01011111 00110111 00110011 01110011 00110011 01110010
00110100 01100011 00110111 01011111 00110001 01110011 01011111 00110100
01011111 01110110 00110011 01110010 01111001 01011111 01100111 00110000
00110000 01100100 01011111 01110100 00110000 00110000 01101100 00100001
01111101
```

[Decode it](https://www.dcode.fr/ascii-code)


Flag: `n00bz{7h1s_1s_4_v3ry_l0ng_fl4g_s0_th4t_y0u_c4nn0t_s0lv3_7h3_ch4ll3ng3_m4nu4lly_b7w_73s3r4c7_1s_4_v3ry_g00d_t00l!}`