ffmpeg concat command not reading input file correctly - command-line

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

Related

How can I read a zipped CSV file with KDB?

I've got a number of CSV files saved with pandas as zip files. I'd like to read them into KDB without having to manually unzip them in a terminal beforehand.
It looks like KDB supports compression:
https://code.kx.com/q/kb/file-compression/
But I can't figure out how to get it to decompress it. What I read in looks like the literal zip file.
How do I read a zipped CSV file in KDB?
Named pipes can be used for this purpose
https://code.kx.com/q/kb/named-pipes/
q)system"rm -f fifo && mkfifo fifo"
q)system"unzip -p t.zip t.csv > fifo &"
q)trade:flip `sym`time`ex`cond`size`price!"STCCFF"$\:()
q).Q.fps[{`trade insert ("STCCFF";",")0:x}]`:fifo

Exiftool: Want to output to one text file using -w command

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"

PDFtk: Merge PDF Problems

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.

Can we give two files as input while using JasperStarter

I am using JasperStarter to create pdf from several jrprint files and then print it using JasperStarter functtions.
I want to create one single pdf file with all the .jrprint files.
If I give command like:
jasperstarter pr a.jprint b.jprint -f pdf -o rep
It does not recognise the files after the first input file.
Can we create one single output file with many input jasper/jrprint files?
Please help.
Thanks,
Oshin
Looking at the documentation, this is not possible:
The command process (pr)
The command process is for processing a report.
In direct comparison to the command for compiling:
The command compile (cp)
The command compile is for compiling one report or all reports in a directory.

Using libav without generating output file

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.