Shailendra Paliwal <beingshailendra@xxxxxxxxx> writes: > On Sat, May 5, 2018 at 4:43 PM, Måns Rullgård <mans@xxxxxxxxx> wrote: > >> Shailendra Paliwal <beingshailendra@xxxxxxxxx> writes: >> >> > Hello, >> > >> > I found sox as a command-line equivalent of Audacity. I was wondering how >> > can I glitch images like the way I can using Audacity. >> > >> > On audacity the usual modus operandi is, >> > >> > 1. Use Audacity > File > Import > Raw Data, to import a BMP image >> file. >> > 2. Set the encoding to U-Law or A-Law. >> > 3. Apply audio effects to the track. >> > 4. Export Audio, set Save As Type > Other Uncompressed Files >> > 5. Header > RAW (header-less) and Encoding > whichever selected in (2) >> > 6. Rename to BMP >> > >> > I was wondering if the same method can be used with sox. That way I can >> > make shell scripts to glitch images or even thousands of frames in a >> video. >> >> Yes, this can be done. Try something like this: >> >> $ sox -t ul -c 1 -r 48k input -t ul output effects... >> > This seems to corrupt the header of the file too and then I cannot open it > at all. Usually in Audacity, I would not touch the first 5% of the track > assuming it contains the header information that should be left untouched. Yes, of course. I assumed you had some way of dealing with that. > So, I thought if I can split the header and the file contents into two > file. That would be easy to run through sox. > > I tried > $ sox -t ul -c 1 -r 48k water.bmp -t ul water_out trim 0 15 : newfile : > restart > > This should work because new headers aren't created while spitting and I > checked this by merging these files back (I'm on windows) > $ type water_out* > water_databent.bmp You should also be able to simply do this: $ sox -t ul -c 1 -r 48k water.bmp -t ul water_out trim 0 100s : effects ... That will pass through the first 100 samples (enough to skip the BMP header) unchanged, then apply the specified effects to the remainder of the file. > This get me the image again. > > However, I processed one chunk with an audio effect and the file size > reduced drastically from ~700KB to ~2KB. Would you know why did that > happen? I did > $ sox -t ul -c 1 -r 48k water_out002 -t ul water_out002 echo 0.8 0.7 45 0.31 If you trimmed 15 seconds from the start of the file, that would be about 700 kB at 48 kHz. -- Måns Rullgård ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users
