[M4IF Technotes] 8 bit padding before startcodes?

[Herbert Thoma]

Christoph Lampert schrieb:
> 
> Hi,
> 
> is it mandatory to have at least 1 bit of padding before any
> start_code? So it is possible that 8 bits are needed?
> Or should it be 0 bits then?

No, it is not mandatory before any start_code. The 1-8 padding
bits result from the next_start_code() function in the syntax
description. This appears for example after VideoObjectLayer()
and after VideoObjectPlane(), so you get padding bits before
every VOP start code.
> E.g. in VisualObjectSequence(), if there is no user_data,
> then always 40 bits = 5 bytes will have been written before
> the VisualObject could start:
> 32 bits for visual_object_sequence_start_code  and
>  8 bits for profile_and_level_idication.
> 
> Will there be 8 bits = 0x7F of padding then, before
> visual_objects_start_code, or no bits at all?

In the syntax description there is no call to the
mext_start_code() function before VisualObject(),
i.e. there should be 0 bits here.
Regards,
 Herbert.
> Best regards,
> Christoph
> 
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Herbert Thoma
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