[MPlayer-users] dcs-5300G video.vam howto play it

[Raphael]

Reimar Döffinger wrote:
> Hello,
>   
>> the dcs-5300G is a dlink camera. 
>> The specs say
>>
>> "H.263+ (MPEG4 short header mode)"
>>     
>
> Whatever you downloaded it is not H.263+, the picture header is invalid
> according to all (draft) specifications I could find.
> Now, I can't say anything about "MPEG4 short header mode", since MPEG-4
> specifications (even as drafts) are really hard to come by...
>   


A quick web search shows some information about MPEG 4 short header mode.

See from http://www.m4if.org/resources/mpeg4userfaq.php

"

# *Does MPEG-4 Video support H.263?*

Yes. H.263 Baseline (No Annexes) is incorporated as part of MPEG-4. It 
is known as 'short header' inside the specification.

# **

"


or from 
http://www.dipol.com.pl/bib103e.htm#Why%20MPEG-4%20ASP%20is%20better%20than%20Short%20header

"

There are different kinds of MPEG-4 compression. The most popular are 
MPEG-4 ASP (Advanced Simple Protocol), MPEG-4 SP (Simple Protocol), or 
MPEG-4 Short Header. MPEG-4 ASP generates frames of I, P and B type, 
which improves compression factor, whilst MPEG-4 SP and MPEG-4 Short 
Header give only I and P frames. MPEG-4 ASP and MPEG-4 SP are 
implemented on ASIC chips (Application Specific Integrated Circuit), 
whereas MPEG-4 Short Header uses DSP circuit (Digital Signal Processor). 
The answer is: with the same picture quality the band needed for 
transmission is considerably lower, or - with the same band - the 
quality of picture is higher.

"

or from 
http://www.axis.com/documentation/whitepaper/video/compression_standards.htm

"

*3.6.3 MPEG-4 short header and long header
*Some network video streaming systems specify support for “MPEG-4 short 
header,” so it’s important to understand this term. In fact it’s nothing 
more than an H.263 video stream encapsulated with MPEG-4 video stream 
headers.

MPEG-4 short header does not take advantage of any of the additional 
tools specified in the MPEG-4 standard. MPEG-4 short header is only 
specified to allow backwards compatibility with the H.263 recommendation 
for video conferencing over ISDN and LAN. For practical purposes, MPEG-4 
short header is identical to H.263 encoding/decoding, which gives a 
lower quality level than both MPEG-2 and MPEG-4 at a given bit-rate. The 
image and video quality in “short header” is not close to that of true 
MPEG-4, since it does not make use of techniques that allow it to filter 
out picture information that is not visible to the human eye. Nor does 
it use methods like DC and AC prediction, which can significantly
decrease bandwidth demands.

To clarify a network video streaming system specification, support for 
MPEG-4 is sometimes denoted “MPEG-4 long header,” which in other words 
is the mode where the MPEG-4 compression tools are being used.
"

Raphael