I use libav for an application in which transform coefficients of video should extracted. But the output file of libav is not important in this application. There is memory limitation and I don't want produce the output file.
I read some documentations about libav along with its help. But I couldn't solve this issue. How can force libav from producing the output file?
If you want to decode your file without output, you can use the following approaches:
1: specify its output format as null
2: specify its output as null:
In windows and linux you can use this command:
avconv.exe -i input.mkv -f null null
./avconv -i input.mkv -f null /dev/null
Base on (ffmpeg description) -f Force input or output file format. The format is normally auto detected for input files and guessed from the file extension for output files, so this option is not needed in most cases.
And The second null specify its output as null.
Related
I'm currently trying to use exiftool on Windows command prompt to read meta data from multiple files, then output to a single text file.
The exact command I last tried looked like this:
exiftool.exe -FileName -GPSPosition -CreateDate -d "%m:%d:%Y %H:%M:%S" -c "%d° %d' %.2f"\" -charset UTF-8 -ext jpg -w _Coordinate_Date.txt S:\Nick\Test\
When I run this, I get 7 individual text files with the content for one corresponding file in each of them. However, I simply want to output all of it to one single text file. Any help is greatly appreciated
The -w (textout) option can only be used to write multiple files. It is not meant to be used to output to a single file. As per the docs on -w:
It is not possible to specify a simple filename as an argument -- creating a single output file from multiple source files is typically done by shell redirection
Which is what you're doing with the >> ./output.txt part of your command. The -w _Coordinate_Date.txt isn't doing anything and I would think throw an Invalid TAG name: "w _Coordinate_Date.txt" error if quoted together like that as it gets treated as a single arugment. The -w option requires two arguments, the -w and either an extension or a format string.
I actually figured it out, if you wrap the entire -w _Coordinate_Date.txt command in quotations and append it to a file, you can throw all of the output into one text file.
i.e. "-w _Coordinate_Date.txt >> ./output.txt"
I am trying to concatenate two video files using ffmpeg, and I am receiving an error.
ffmpeg -f concat -safe 0 -i list.txt -c copy concat.mp4
And the error output I receive is....
[concat # 0x7ff922000000] Line 1: unknown keyword '43.mp4'
list.txt: Invalid data found when processing input
It looks like that the file names in the list have to be specially formatted to look like:
file '/path/to/file1.wav'
with a word file included. I spent a lot of time trying to guess why ffmpeg encountered an error trying to read the file names. It didn't matter if they were in the list or in the command line. So only after I utilized a command
for f in *.wav; do echo "file '$f'" >> mylist.txt; done
to make list from ffmpeg's manual I had success. The only difference was an additional word file.
Here you can read it yourself: https://trac.ffmpeg.org/wiki/Concatenate#demuxer
I have managed to use
tesseract image.jpg output.txt
to read the text on an image file and save it as a text file, but now I am trying to use more specific commands with tesseract and it is trying to open the output file rather than saving into it
I am trying to use
tesseract image.jpg stdout -c tessedit_char_whitelist=ABCDEFGHIJKLMNOPQRSTUVWXYZ%/-15 TextOutput
I have literally just started using tesseract so I may well be making a stupid mistake
I figured out that if you insert a > after the specific commands it works
like this
tesseract image.jpg stdout -c tessedit_char_whitelist=ABCDEFGHIJKLMNOPQRSTUVWXYZ%/-1250 > TextOutput.txt
Is it possible to pass pre-captured binary files through snort for analysis (with flagging or detection as the ultimate goal)?
You can use -r option for that
I am using PDFtk (Version 2.02, UNIX) for merging PDF and facing below problems in the output PDF:
Initial View of the PDF is changed (should open with Bookmarks Panel and Page)
Bookmarks doesn’t point to the exact linked section as in the separate PDFs (shows fit page of the section)
Original metadata is lost (should retain first PDF's metadata)
Please suggest any workaround for the above points.
Regards,
Umesh
It's a little late to answer, but I came across this question while looking for a solution to the same problem. After taking a look at the man of pdftk I found a solution and I made a little script:
#!/usr/bin/env bash
# pdfcat
array=( $# )
len=${#array[#]}
merged=${array[$len-1]}
pdf2merge=${array[#]:0:$len-1}
pdftk $1 dump_data output metadata
pdftk $pdf2merge cat output $merged
pdftk $merged update_info metadata output out
mv out $merged
rm metadata
exiftool $merged
The script save the metadata of the first PDF file (first argument) and write it to a file called metadata. Then it uses the cat command of pdftk to merge all the files (the output file is the last argument). Finally it loads metadata's content to the metadata of the resulting file before erasing metadata. The last line uses exiftoolto print the metadata of the resulting file in order to check if everything went well.
You can save this script to your home/username/bin directory, make it executable with:
$ chmod u+x scriptname
and then you can use it to merge files with the following syntax:
$ scriptname 1.pdf 2.pdf 3.pdf output.pdf
The resulting output.pdf will have the same metadata as the original 1.pdf file.