Videogrep: Difference between revisions

Revision as of 21:35, 7 October 2010

aka grep meets SRT

The idea of this assignment is to familiarize yourself with:

basic text/code editing in Linux
commandline basics
big idea: working in a "pipeline" (both literally, and more metaphorically)

Ingredients

Plain text?

ISO-8859
UTF-8

file nameofyourfile.srt

Redirecting stderr to stdout

ffmpeg's output is actually to the stderr and not the stdout. In other words, the output is tagged as 'error information', and the ability to distinguish between this and "regular" information can sometimes be useful. In this case however, we want ffmpeg's output to be treated like "regular" command output. You do this by "redirecting stderr to stdout" with the cryptic addition of "2>&1".

ffmpeg -i foo.ogg 2>&1

[1]

Search & Replace

sed is good for search and replace...

sed s/a/*/g from to

http://www.archive.org/details/night_of_the_living_dead

@@ Line 15: / Line 15: @@
 === Redirecting stderr to stdout ===
-ffmpeg's output is actually to the "stderr" and not the stdout. In fact they both appear on the screen -- but the ability to distinguish between these two different "sources" or types of information can be very useful. In this case, we want to erase the distinction so that "errors" are treated like regular output.
+ffmpeg's output is actually to the ''stderr'' and not the ''stdout''. In other words, the output is tagged as 'error information', and the ability to distinguish between this and "regular" information can sometimes be useful. In this case however, we want ffmpeg's output to be treated like "regular" command output. You do this by "redirecting stderr to stdout" with the cryptic addition of "2>&1".
   ffmpeg -i foo.ogg 2>&1