[MPlayer-users] Error messages when encoding HDTV
Steven M. Schultz
sms at 2BSD.COM
Thu Dec 25 19:16:50 CET 2003
On Fri, 26 Dec 2003, Adam Nielsen wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > > > size restrictions for MP at ML or MPEG1 exceeded! (1920x1088).000 [834:102]
>
> > I think it's exeeding MPEG1 limits, as they are quite low
MPEG1 is limited to around 4096x4096 or so ;)
When people say "MPEG1 is limited" what they are really talking about
is the VCD format which uses a very restricted subset of MPEG-1
called CPB ("Constrained Parameters Bitstream") and that is limited
to 1152 Kbits/s, constant bitrate, 396 macroblocks/frame, and so on.
> That's what I gathered, but why would it print this when it's an MPEG-2
> stream? Unless it means that it's either exceeding MPEG1 specs or MPEG-2's
> MP at ML specs?
It is printing those messages out (and I have seen them too) because
MPEG-2 streams are characterized by "Level" and "Profile with Level" .
MP at ML means 'main profile' at 'mail level'.
Low Level = MPEG1 Constrained Parameter Bitstream, up to 352x288 at
30 frames/sec, maximum of 4Mb/s
Main Level = MPEG2 Constrained Parameter Bitstream, up to 720x576 at
30 frames/sec, maximum of 15-30Mb/s
High 1440 Level = up to 1440x1088 at up to 60 frames/sec and intended
for HDTV applications, maximum bitrate is 60 to 80 Mb/s
High Level = up to 1920x1088 at up to 60 frames/sec and intended for
HDTV, max bitrate is 80 to 100Mb/s
The various profiles ("SP", "MP", "MVP", "422P") specify additional
features and/or restrictions ("422P" adds 4:2:2 to the High and Main
profiles for example).
So if a player is geared towards MP at ML then it will complain when
given a MP at HL stream
> I don't know whether this message causes any frames to be skipped though (my
> computer is waaay to slow to decode HDTV in realtime, and the resolution is
> too high for the xv overlay of my GF2 anyway) so I guess as long as all the
On my nvidia 5200 I use '-vc ffmpeg12mc' and the clip plays smoothly
and without dropping any frames (and uses almost no cpu time since
the decoder in the video card is doing most of the work).
I was using a Matrox card until a few weeks ago but those all have
a Xv overlay of only 1024x1024 where the nvidia GF4 and up are
around 2048x2048.
> frames are displayed it wouldn't matter. Does anyone who has a fast enough
> PC know whether any frames are dropped?
HDTV resolution in software only playback is slow even on a Athlon
2800 (well, it's a dual but that doesn't matter for this).
Cheers,
Steven Schultz
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