add support for stdin

[avium]

Why not support stdin for use with smaller files?

[danielgtaylor]

Currently the script needs to be able to do random seeks within the file, which is difficult from stdin (basically you need to load the file into memory, or write to a temp file and then process it as if it were passed in instead of stdin). What's the use case for this change? Why would you need something like this?

[alexellis]

One use-case which brought me here is for creating "serverless" functions where you may not have write access to the filesystem, you can however work with pipes. Basically this works perfectly with files, but not with stdin/stdout - https://gist.github.com/dergachev/4627207

Your tool appears to be able to re-arrange MOV files so that they can be piped into ffmpeg, but requires them to be written to disk - which defeats the point.

[pierre-fribourg-context]

One use-case which brought me here is for creating "serverless" functions where you may not have write access to the filesystem, you can however work with pipes. Basically this works perfectly with files, but not with stdin/stdout - https://gist.github.com/dergachev/4627207

Your tool appears to be able to re-arrange MOV files so that they can be piped into ffmpeg, but requires them to be written to disk - which defeats the point.

Got the same use-case.
I have MP4 videos with moov atom at the end of the file, I am trying to make serverless functions to move the moov atom at the begining of the file.
As I don't have hdd or memory enough for big file to actually write them, I have to process them in chunks while downloading & pipe data through stdin getting result from stdout and uploading them away on the go.
Would be nice if this tool support in & out through standards i/o as for now I found yet any solution to move a moov atom without downloading the whole file first.