[FFmpeg-user] dvdsubs

[Carl Zwanzig]

On 6/26/2025 10:32 AM, Mark Filipak wrote:
> Z. please stop implying that I don't search for answers.

At least an appearance of doing that, the first email of this thread did 
not; maybe tell us what you found, where, and why it doesn't answer the 
questions. Even question your own assumptions, like "it doesn't look 
like a bit map but everyone says it is" - is everyone else wrong or are 
you missing some essential info or looking at it in the wrong way? 
(That's basic scientific method.)


On 6/26/2025 12:39 PM, Mark Filipak wrote:
> but I'm going by what I see, not by the crap on the Internet.
'crap' is a strange description for something the Library of Congress 
published, did you read it? Maybe you should send them a correction.


_Another_ quick search turns up a quite in-depth description of the 
subtitle stream*, including the image itself. Among other things, the 
lines are interlaced -and- the pixels are run-length encoded, plus color 
info is included (from a palette defined elsewhere) -

(a small quote from https://sam.zoy.org/writings/dvd/subtitles/)
The pixels are run-length encoded. The one byte values are :
      one byte values : 0xf 0xe 0xd 0xc 0xb 0xa 0x9 0x8 0x7 0x6 0x5 0x4
      two byte values : 0x3* 0x2* 0x1*
       3 bytes values : 0x0f* 0x0e* 0x0d* 0x0c* 0x0b* 0x0a* 0x09* 0x08* 
0x07* 0x06* 0x05* 0x04*
       4 bytes values : 0x03** 0x02** 0x01** 0x000*

- in a hex display it's not going to look like a bitmap no matter how 
much you want it do.

*it -is- a stream, that's what mpegts carries.

Why does the header "appears to have been copied, verbatim, from the 
MPEG2TS."? It probably was. Look at how the subtitle -images- are 
carried in the stream.

Maybe your eye should look closer.

z!