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Constant bitrate control for H.263 encoder.

dierssen
Beginner
122 Views

Hi.

I implemented a constant bitrate control algorithm in the IPP 5.0 H.263 encoder, similar to the RateControl=2 bitrate control of the MPEG4 encoder. However, I see some artifacts (see attached file). They are the same artifacts I saw, when I used the MPEG4 encoder RateControl=2 option.

I know that these artifacts were solved for MPEG4 in the IPP5.1 examples. What I want to know is: which fixes were done for MPEG4 in IPP5.1 to remove these artifacts? I hope,I can add the same fixes to the H.263 encoder of 5.0.

Greetings Werner.

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3 Replies
Vladimir_Dudnik
Employee
122 Views

Hi Werner,

Could you try the simplest way, side by side comparison of sources (I think they are not changed significantly)?

Regards,
Vladimir

dierssen
Beginner
122 Views

Hi!

Well, I implemented the rate control, according to the example of MPEG4. I just added DQUANT functionality.Some remarks:

EncodeMCBPC_I in h263_enc_frame.cpp. According to the H263 specification I changed the 7 into a 6.

In EncodePVOP of ippvideoencodermpeg4_vop.cpp. mNumNotCodedMB should be decreased when MBcurr->not_coded is set to 0 in the if (quant < VOP.vop_quant || dquant != 0) statement. When you do not do this mNumNotCodedMBcan get values larger than mNumMacroBlockPerVOP and this results invideo artefacts.

Greetings Werner.

Vladimir_Dudnik
Employee
122 Views

Hi Werner,

thanks for sharing that info with the community

Regards,
Vladimir

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