How to force SKIP mode in encoder

[starter_haha]

Dear all,

I am asking some help regarding force HHI encoder to use SKIP mode with specific macroblock, more specifically as below:

Let's say I have a test sequece frame i{i = 1, 2, M}, each frame there
is macroblock j{j = 1, 2, N}. I would like to force encoder to use SKIP mode
with any (i, j).

I am using HHI reference software to do this.

Any suggestion will be highly appreciated!

starter.

[DarkZell666]

Unless I'm really mistaken this is a bad and useless idea (I'm not the expert) since SKIP means IIRC "don't code the macroblock, just use a reference to the previous one" ... (akupenguin will sort me out on that one :P)

Maybe you could give further explanation on what precisely you are trying to do ? I believe it's the encoder's job to decide (according to the motion vectors, if any) which mode to apply to each macroblock.

[starter_haha]

The purpose is to study the impairment of missing coded Microblock as oppose to successfully receiving it. I assume this is the concealment
that decoder will operate. This seems only true for P-Slice though.
Anybody have an idea of I-Slice case? I mean if one MB is missing at
decoder, what would it do? Using last decoded MB?

Thanks a lot!

starter

[akupenguin]

Yes, assuming B/P-skip is a sane method of concealment. But if one macroblock is corrupted, it's very unlikely that you'll be able to decode anything further in the slice. So don't just skip single blocks. Plus, imho the most common corruption in streaming is missing whole slices.
If you expect corruption, you should be using data partitions. Which have yet again different failure modes.
Why do you have to simulate corruption, as opposed to encoding normally and then really corrupting the file?

[starter_haha]

Hi akupenguin,

Sounds good. I still kept my eye open for other way to evaluate corruption.
At the meantime, any suggestion to simulate I-slice other than corrupt file
itself?

Thanks a lot!

Yijing