# ffmpeg: download streams, trim video, concat files ### Download individual stream files ```bash ffmpeg -i -c ``` Start with the `ffmpeg` command `-i` = input file `` either a stream url or local file `-c` = codec to be used ``\= I always use `copy` to use the same codec as the stream, or you can specify any other codec you want `` = the filename you want to save ### Trim the parts you don't want ```bash ffmpeg -ss -i -to -c ``` Start with the `ffmpeg` command `-ss` = start time of the video to trim `` = must be in the format of hours:minutes:seconds `-i` = input file `` either a stream url or local file `-to` = total length of clip time, this can be confusing at first because you need to calculate the elapsed time of the clip. e.g. If you want to trim a clip that begins at 01:23:33 (one hour, 23 minutes, 33 seconds) and you want the video trimmed to 01:23:55 (one hour, 23 minutes, 55 seconds), the value of `to` would be `00:00:22` (22 seconds elapsed time) `-c` = codec to be used ``\= I always use `copy` to use the same codec as the stream, or you can specify any other codec you want `` = the filename you want to save, make sure you create a copy and don't overwrite the original file you are trimming ### Save all your files with a consistent naming pattern to easily collect them for future use ```bash for f in ; do echo "file '$f'" >> ; done ``` let's write a bash script to easily create a playlist of the files you want to concat `for in` is a bash loop to find all instances of the pattern given `f` is a variable name for "file", it could be anything `` is a regex pattern of the filename e.g. `*title-mm-dd-yy*` `do` begins the looping process `echo "file '$f'"` tells bash to write the text `"file "` from the variable `f` to stdout (the terminal) `>>` is a direction operator in Linux to write a file. When two arrows are present, it signifies append to the existing file `` should be a text file e.g. `files.txt` `` is used to end the previous command we need to finish with a `done` command to finish the loop This will create a `files.txt` with a playlist of the matching files > file 'game-01-01-23\_1.mp4' > > file 'game-01-01-23\_2.mp4' > > file 'game-01-01-23\_3.mp4' > > file 'game-01-01-23\_4.mp4' ### Concat your files ```bash ffmpeg -f concat -i -safe 0 -c ``` Start with the `ffmpeg` command `-f`\= indicates to ffmpeg to list each file for concatenation `concat` = concatenate command `-i` = input file `` either a stream url or local file `-safe 0` = dictates unsafe file names should be ignored, this is mainly used to allow relative paths `-c` = codec to be used ``\= I always use `copy` to use the same codec as the stream, or you can specify any other codec you want `` = the filename you want to save, make sure you create a copy and don't overwrite the original files you are using to create the final version