[FFmpeg-devel] [PATCH] Dump info for all streams (not just those known to be in a program)

Måns Rullgård mans
Sat Nov 10 14:21:10 CET 2007

Wolfram Gloger <wmglo at dent.med.uni-muenchen.de> writes:

> Hi,
>> Streams without a PMT entry should be ignored.  There is nothing we
>> can sensibly do with them.
> I disagree.  Auto-detection works fine for most stream types,
> in particular for DVB streams.  This has worked for years.

It worked through coincidence and luck.  In the past you could be
almost certain that an MPEG-TS stream used MPEG2 video and MPEG audio.
With H.264 and AAC on the rise, this is no longer the case.

It was utterly stupid of whoever wrote those DVB tools years ago to
drop the PSI tables, and it's about time they paid the price.

> The 'program' changes, although adding a nice feature, have
> removed information from dump_format that was present
> before.  My patch just restores the previous behaviour w/o
> impeding the new feature in any way.

The previous behaviour was wrong.  FFmpeg should not be making
unreliable guesses.

>> If someone has a file with missing/bad PMT, they can always create
>> a proper one and prepend it to the file.
> How so?  If you have a tool that does this, I'd be interested.
> But I suspect it wouldn't do much beyond what the ffmpeg autodetection
> does.

It always possible to inspect the file manually and figure out what's
what, and writing a PMT is easy enough with any hex editor.

M?ns Rullg?rd
mans at mansr.com

More information about the ffmpeg-devel mailing list