• Compression Techniques

  ffmpeg: Using -b option with -target pal-dvd

  Posted by Steve Hearn on July 31, 2011 at 2:41 am

  I’m converting a .ts file from a set top box to a mpg file using:

  ffmpeg -i data0001.ts -target pal-dvd data0001.mpg

  Works great. However, the output file is large, so I’d like to sacrifice some resolution to get the size down.

  I tried to use the -b option as follows:

  fmpeg -i data0001.ts -target pal-dvd -b 2048 data0001_2048.mpg

  I do get a smaller file (about 5 times smaller), but quite pixelated. Problem is I get the same size/quality no matter what value I use for -b. That is I tried -b 1024,2048,4096 etc etc and I always get approximately the same output size/quality.

  I dont really have any control over size/quality.

  Am I allowed to use the -target and -b together?

  Steve

  Steve Hearn replied 15 years ago 2 Members · 2 Replies
• 2 Replies

• 

  Michael Rampe

  July 31, 2011 at 5:09 am

  [steve hearn] ” That is I tried -b 1024,2048,4096 etc etc and I always get approximately the same output size/quality.”

  The -b option is specified in bits.

  Try 1024k, 2048k etc. instead. (1M and 2M also work as do 1024000, 2048000)

  Michael
• 

  Steve Hearn

  July 31, 2011 at 10:07 am

  Michael

  Thanks very much for your rapid reply. That explains it! I seem to be getting
  much more sensible results now.

  Steve

Reply to this Discussion! Login or Sign Up