[Mp4-tech] H264 Corrupted Bitstreams

[Shankar Manuel Aghito]

You can use this simple matlab script to create your corrupted
bitstreams, i.e. with missing NALUs
function removenalus(filename,damagefilename,naluindexes)
% Load the uncorrupted stream
fid=fopen(filename);
data=fread(fid,'uint8');
fclose(fid);
% Find initial position of NALUs
nalus=(filter([1 2 2 2],1,[1; 1; 1; data])==1);nalus=nalus(4:end);
nalupositions=find(nalus)-3;
% Find the length of the NALUs
nalulengths=[nalupositions(2:end);length(data)+1]-nalupositions;
% Order the NALUs to be removed
for i=sort(naluindexes,'descend')
    data(nalupositions(i):nalupositions(i)+nalulengths(i)-1)=[];
end
% Save the stream with removed NALUs
fid=fopen(damagefilename,'w');
data=fwrite(fid,data,'uint8');
fclose(fid);
----------
Example:
removenalus('test.264','test_damaged.264',[10 20 35])
Will create the corrupted bitstream test_damaged.264 by removing the
10th, 20th and 35th NALUs from test.264
This will only work if you set the encoder and decoder to work with
Annex B output format, not RTP.
this is an implementation of what is described in
http://lists.mpegif.org/pipermail/mp4-tech/2006-October/006919.html
best regards,
Manuel
	-----Original Message-----
	From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of arun menon
	Sent: 15. oktober 2006 08:31
	To: mp4-tech lists.mpegif.org
	Subject: [Mp4-tech] H264 Corrupted Bitstreams
	Dear Friends,
	I want to test the robustness of my H264 decoder and was looking
out for some corrupted h264 bitstreams. I would really appreciate if you
can help me in this regard. I would like to know if there is any site
from where i can download the same.
	Thanks,
	Arun 
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