Do you have any plan to use DWT coefficients coding to achieve efficient compression by using any kind of compression algorithms such as EZW, ZTE, SPIHT...etc. ? If so, which algorithm do you intend to use. Let me know. I believe that there is no such algorithm in current version of DIRAC according to the specification 0.9.
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We don't intend to use any zerotree wavelet coding algorithms. Firstly, they're heavily patented. Secondly, they don't work that well for motion-compensated difference pictures. And thirdly, it's not so easy to apply perceptual weighting.
Thomas
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Thank for your reply. Basically, I am doing Error Resilient coding for DIRAC. One thing I still wish to know is how often do the encoder restart the I frame coding in motion estimation and compensation ? I mean the distance between the first and second I frame in term of the number of frame.
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The frequency of I frames is up to you. If you use the default settings then for -stream they're every 36 frames; for -SD576 they're every 12 frames; for -HD720 they're every 24 frames; and for -HD1080 they're every 12 frames.
In general, the length of the GOP is (num_L1+1)*L1_sep. L1 frames are like P frames in MPEG, and num_L1 is the number between I frames, and L1_sep is the number of frames from one L1 frame to the next.
So if you set
-num_L1 0
you'd get I frame only coding, overriding any presets. If you set
-num_L1 99 -L1_sep 5
then there would be 500 frames from one I frame to the next.
cheers
Thomas
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Thank for your information. No, I am not intending to post the code anywhere. Once completed, I will post directly to BBC R&D. Currently, we are in the process of developing the ideas for Error Resilient Coding and hoping to submit the report about this probably within next week.
Regards,
MYO TUN
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Dear Dirac Developers,
Do you have any plan to use DWT coefficients coding to achieve efficient compression by using any kind of compression algorithms such as EZW, ZTE, SPIHT...etc. ? If so, which algorithm do you intend to use. Let me know. I believe that there is no such algorithm in current version of DIRAC according to the specification 0.9.
We don't intend to use any zerotree wavelet coding algorithms. Firstly, they're heavily patented. Secondly, they don't work that well for motion-compensated difference pictures. And thirdly, it's not so easy to apply perceptual weighting.
Thomas
Thank for your reply. Basically, I am doing Error Resilient coding for DIRAC. One thing I still wish to know is how often do the encoder restart the I frame coding in motion estimation and compensation ? I mean the distance between the first and second I frame in term of the number of frame.
The frequency of I frames is up to you. If you use the default settings then for -stream they're every 36 frames; for -SD576 they're every 12 frames; for -HD720 they're every 24 frames; and for -HD1080 they're every 12 frames.
In general, the length of the GOP is (num_L1+1)*L1_sep. L1 frames are like P frames in MPEG, and num_L1 is the number between I frames, and L1_sep is the number of frames from one L1 frame to the next.
So if you set
-num_L1 0
you'd get I frame only coding, overriding any presets. If you set
-num_L1 99 -L1_sep 5
then there would be 500 frames from one I frame to the next.
cheers
Thomas
Are you intending to post your code somewhere?
Thomas
Thank for your information. No, I am not intending to post the code anywhere. Once completed, I will post directly to BBC R&D. Currently, we are in the process of developing the ideas for Error Resilient Coding and hoping to submit the report about this probably within next week.
Regards,
MYO TUN