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Old 12th February 2014, 06:57   #61  |  Link
ricci
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Originally Posted by pieter3d View Post
I am assuming you are trying to modify the way a CU is predicted? In that case you will want to augment the functions in TComPrediction.cpp
Not really no. I should have explained better sorry. Im working on 3D-hevc, specifically with the depth maps. Now I'm trying to follow a paper (i.e. http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6611943&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6611943)

This paper uses the collocated texture luma block to try to simplify one mode of wedgelet predictions. From the two lines of code I pasted before, (I think) I am finding this collocated texture luma block. Once this block is found, the paper applies a 1-d filter on each of its side. Now to this this, I am assuming that he must extract the pixels of this block in order to do so. That is where I am having difficulties. What I mainly want to do is extract the pixels of this block (and possible save them in this temp new block), apply the 1-D filter to each of its sides, and continue from there.
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Old 12th February 2014, 07:00   #62  |  Link
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PM me your gtalk name, we can discuss tomorrow morning (Pacific time). Doesn't look like this will be as easy as you hope
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Old 25th February 2014, 17:09   #63  |  Link
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So, if I have a Core 2 E6750 it's rather unlikely that I'll be able to play FullHD HEVC vides, right?
Tried one sample, which was really choppy.
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Old 27th February 2014, 01:56   #64  |  Link
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So, if I have a Core 2 E6750 it's rather unlikely that I'll be able to play FullHD HEVC vides, right?
Tried one sample, which was really choppy.
If encoded with Wavefront Parallel Processing, maybe. But you've only got two cores, I think without hyperthreading.
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Old 28th February 2014, 10:11   #65  |  Link
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Quantization scale matrices

Hi what is the significance of Quantization Scale Matrices in HEVC. Can any one explain in detail or provide any good References.
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Old 1st March 2014, 00:25   #66  |  Link
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Hi what is the significance of Quantization Scale Matrices in HEVC. Can any one explain in detail or provide any good References.
It's basically identical to H.264/AVC's quantization, scaled up, which is very similar to MPEG-1,2, and 4's, which are nearly the same as JPEG's quantization. Wikipedia has a very basic overview, then you can see page 8 of this H.264 overview (pdf) for more specific information about it, and the mathematics behind it. There were some great visual explanations from akupenguin and Dark Shikari here years ago, but I can't find them now.
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Old 3rd March 2014, 14:07   #67  |  Link
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Thanks, but in HM code he is using some Default matrices, for example all 16's etc. When i change some numbers still i am getting same bit rate and quality...what might be the reason
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Old 7th March 2014, 00:38   #68  |  Link
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Thanks, but in HM code he is using some Default matrices, for example all 16's etc. When i change some numbers still i am getting same bit rate and quality...what might be the reason
Do you mean that you changed g_quantTSDefault4x4? Did you set ScalingList to 1? Because unless you specify using a custom scaling list, it always scales by a scalar (flat "matrix") no matter what you change to g_quantTSDefault4x4 and g_quantIntraDefault8x8 to. Those lists are built-in custom quant matrices (even if they are flat), not the standard scalar. In rExt, it's a separate value, g_quantScales; in HM, it was a bit-shift, not sure if it uses g_quantscales now too.
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Old 9th March 2014, 03:31   #69  |  Link
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Yes Thanks, i have set ScalingList as 1 and now i got different values. Basically i need some already done Research papers on usage of user defined Scale Matrices for Good Compression Compared to Default Matrices. I do not have any idea of how to Manipulate the values to get better Results. Also they are using Same matrices for Chroma and Luma. One more Query is g_quantTSDefault4x4 and g_quantIntraDefault8x8 are Default matrices. But g_QuantScales is an array with 6 values, can you tell what for this array is used.
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Old 9th March 2014, 20:37   #70  |  Link
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Related question: does H.265 support custom quantization matrices at all, like H.264 does in high profile?
/In the currently available Main and Main 10 profiles.../
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Old 9th March 2014, 23:29   #71  |  Link
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Related question: does H.265 support custom quantization matrices at all, like H.264 does in high profile?
/In the currently available Main and Main 10 profiles.../
In the HM, you can customize your configuration in this section...
Code:
#=========== Quantization Matrix =================
ScalingList                   : 0                      # ScalingList 0 : off, 1 : default, 2 : file read
ScalingListFile               : scaling_list.txt       # Scaling List file name. If file is not exist, use Default Matrix.
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Old 8th April 2014, 19:31   #72  |  Link
ricci
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GoP Structure

Hi, could someone confirm if the Group of Pictures Structure for the Random Access Configuration in HM is Hierarchical B Prediction (like the one displayed in: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.84.932&rep=rep1&type=pdf)

The GoP is as follows:

# Type POC QPoffset QPfactor tcOffsetDiv2 betaOffsetDiv2 temporal_id #ref_pics_active #ref_pics reference pictures predict deltaRPS #ref_idcs reference idcs
Frame1: B 8 1 0.442 0 0 0 4 4 -8 -10 -12 -16 0
Frame2: B 4 2 0.3536 0 0 0 2 3 -4 -6 4 1 4 5 1 1 0 0 1
Frame3: B 2 3 0.3536 0 0 0 2 4 -2 -4 2 6 1 2 4 1 1 1 1
Frame4: B 1 4 0.68 0 0 0 2 4 -1 1 3 7 1 1 5 1 0 1 1 1
Frame5: B 3 4 0.68 0 0 0 2 4 -1 -3 1 5 1 -2 5 1 1 1 1 0
Frame6: B 6 3 0.3536 0 0 0 2 4 -2 -4 -6 2 1 -3 5 1 1 1 1 0
Frame7: B 5 4 0.68 0 0 0 2 4 -1 -5 1 3 1 1 5 1 0 1 1 1
Frame8: B 7 4 0.68 0 0 0 2 4 -1 -3 -7 1 1 -2 5 1 1 1 1 0


Also, If it is indeed Hierarchical B, does it make a difference that all frames are as Type B, whilst the POC 8 from the link is a I/P frame?

Thanks.
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Old 19th April 2014, 21:41   #73  |  Link
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Does wavefront in concept like pipelining? Also your description makes it sound like there can only be 2 stages / threads in play for wavefront...will it scale to many-core?
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Old 19th April 2014, 21:44   #74  |  Link
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Its very similar to pipelining. Each CTB row can be decoded in its own thread, so it scales to as many cores as there are CTB rows.
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Old 20th April 2014, 07:34   #75  |  Link
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Does wavefront in concept like pipelining? Also your description makes it sound like there can only be 2 stages / threads in play for wavefront...will it scale to many-core?
Hi puffpio, it sounds like you might be interested in our 4-thread slow-motion wavefront visualisation: http://www.parabolaresearch.com/blog...animation.html
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Old 8th May 2014, 01:21   #76  |  Link
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Why long-term reference pictures are identified by slice_pic_order_cnt_lsb?

I'm trying to understand how DPB management and reference list construction work in H.265. The logic of the recommendation is hard to grasp.

Why short-term reference pictures for the purpose of RPS can only be identified in DPB by PicOrderCntVal, but long-term either by PicOrderCntVal or slice_pic_order_cnt_lsb?

slice_pic_order_cnt_lsb is not unique within a GOP. So there can be a situation that there are two pictures in DPB with the same slice_pic_order_cnt_lsb. How identify a picture for a purpose of a long-term reference then?

What is the reason at all of this complication for long-term reference pictures? Wouldn't it be easier just to use PicOrderCntVal always?
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Old 22nd May 2014, 13:37   #77  |  Link
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intra-prediction implementation by MATLAB

Hi,
I am working on my thesis as implementation of intra-prediction by MATLAB for an image.
I am almost stuck in this thesis.
First of all I need a clear process of how to traverse the image in z-order scan. (how z-scan order really works)
Second I couldn't find so far a very clear description of intra-prediction algorithm.
May someone help me in this regard?
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Old 26th May 2014, 09:48   #78  |  Link
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How about the Reference Management of HEVC? Is there some detailed explanation on it?
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Old 26th May 2014, 22:46   #79  |  Link
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Originally Posted by mas_np View Post
Hi,
I am working on my thesis as implementation of intra-prediction by MATLAB for an image.
I am almost stuck in this thesis.
First of all I need a clear process of how to traverse the image in z-order scan. (how z-scan order really works)
Second I couldn't find so far a very clear description of intra-prediction algorithm.
May someone help me in this regard?
When is your thesis due ? I fear you're a long way from the hard parts.

The first post of this thread is a good place to start.
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Old 31st May 2014, 03:40   #80  |  Link
mas_np
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intra-prediction implementation by MATLAB

Quote:
Originally Posted by benwaggoner View Post
When is your thesis due ? I fear you're a long way from the hard parts.

The first post of this thread is a good place to start.
Actually I couldn't find in any documentation of this standard which clearly explain about following matters:
1- If I am right for detecting which mode should be used for predicting a PU is using the mode with least RD cost with the function: C = DHad + λ ĚRmode
How should I calculate the RD cost?
no specific declaration about what is λ and how should I obtain or calculate it, what is Dhad which has been just translated in "absolute sum of Hadamard transformed residual signal for a PU" and I cannot understand what it exactly is and how should I obtain it?
what is Rmode and how should I calculate or obtain it?

Is it possible to use SAE which was used in h.264 instead of RD cost or something more simpler than RD cost?

2- According to Fig.1 of this pdf:
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.352.3008&rep=rep1&type=pdf

in HEVC there are one row and one buffer columns of samples which is used for prediction of a PU.
Do I always have to have the extension for above reference row from (RN+1,0.. R2N,0) and the extension for left reference column from (R0,N+1.. R0,2N) at the same time or with respect to the selected angle for the block prediction I should have one of these extension at a time for each block?

3- For some angles I should do linear interpolation and for some extrapolation. I couldn't find any method or function to implement these sample generation for reference samples.

4- How should I implement the prediction for angular modes except DC,vertical and Horizontal.

in this patent document:
http://www.google.com/patents/US20130016777

in the paragraph which contains this line:"FIG. 4 shows an embodiment of an intra prediction scheme in a vertical mode"
(Please Find this line in this document)
and the next paragraph there is a clear implementation of vertical and 45 degree modes. However, no clear description on how other angular modes should be implemented could be found neither in this document nor in the previous mentioned PDF in this post.
Moreover, the description for the vertical and 45 degree in this patent document is somehow different from interpolation or extrapolation, isn't it?

Thank you in advance for all further helps...

Last edited by mas_np; 31st May 2014 at 03:56. Reason: Adding something more to the post
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