[MPlayer-users] Re: Problem with mencoder

[D Richard Felker III]

On Mon, Aug 18, 2003 at 05:38:56PM +0200, Oliver Fromme wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> rcooley <rcooley at spamcop.net> wrote:
>  > Oliver Fromme wrote:
>  > > I only use 700M CD-Rs, so the values that frameno prints
>  > > are fine for me.  
>  > 
>  > I was actually refering to the fact that 700MB CDs really hold about 
>  > 703MB normally, and about 720MB with overburning.
> 
> Well, I tend to trust only what is guaranteed, and those
> 80min CD-Rs guarantee 700 MB.  Actually, the CD-Rs that
> I usually buy have a safety margin of 12 seconds (i.e.
> they can hold 80:12), which is 704.8 Mbyte when recording
> with ISO9660 mode1.

703 megs is guaranteed. Do the math. It's 80 minutes, so you have:

  4800 seconds
* 176400 bytes/sec (44100/16bit/stereo audio)
= 846720000 bytes raw space.

That's with 2352-byte audio sectors; in data mode, some is wasted on
error correction, so you only have 2048 byte sectors. Thus

  846720000 bytes total space
* 2048/2352 usable
= 737280000 bytes for data
= 703.125 megabytes

So even after you allow a little space for filesystem/directory
structure, there's sill 703 megs for the movie!

>  > > Even if they were not, I could easily
>  > > calculate them myself, since mencoder prints the bitrate
>  > > of the frameno.avi file.
>  > 
>  > Of course, you could do the same, entirely without frameno.avi.
> 
> How?  When using VBR encoding, the final average bitrate
> cannot be determined without actually encoding the whole
> thing.

I don't understand what you want. If you just want to encode audio
tracks in advance, then dump the ac3 audio and convert it to mp3
separately. No need to use mencoder. But, maybe you want something
else?

Rich