On 02/10/2014 01:41 PM, Steve Borho wrote:



On Mon, Feb 10, 2014 at 1:46 PM, dave <dtyx...@gmail.com <mailto:dtyx...@gmail.com>> wrote:

    On 02/10/2014 10:41 AM, Steve Borho wrote:



    On Thu, Jan 30, 2014 at 12:31 PM, Steve Borho <st...@borho.org
    <mailto:st...@borho.org>> wrote:




        On Wed, Jan 29, 2014 at 5:13 PM, dave <dtyx...@gmail.com
        <mailto:dtyx...@gmail.com>> wrote:

            Hi All,

            I would like to offer my services and contribute to x265
            development.  From the wiki it looks like there are
            plenty things to do but I don't want to duplicate or
            interfere with the work of anyone else so if someone can
            give me something to do I would appreciate it.  I am open
            to anything needed by x265, both c/c++ and assembly work
            though I don't mind being given something simple just to
            get started.  You can find me in the x265 irc channel as
            dtyx265.


        Hi Dave.

        I've been collecting the more pressing TODO items in the
        bitbucket repository's issue tracker:
        https://bitbucket.org/multicoreware/x265/issues?status=new&status=open


        #21 (enabling the VUI message) is the most pressing of the
        "simple" problems.  That would be a great place to start.


    Hi Dave,

    How are things going on this front?

-- Steve Borho


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    I studied the VUI in the h265 spec, appendix E and have been
    studying the x265 code from your suggested starting point,
    setVuiParametersPresentFlag().  It looks like most fields are set
    to spec defaults.  Some look like values that can be options
    specified by the user, others look like values that are calculated
    from encoding a video.

    Can you tell me more about just what pts and dts are?  I
    understand generally what they are but it seems like there are a
    few places in the VUI where they might play a role in calculating
    values.  I haven't had a chance yet to compare to x264 code yet so
    if it all becomes obvious there then I will get it.


pts is the presentation time stamp of a frame, the point at which it is supposed to be displayed by the decoder.

dts is the decode time stamp of a frame, the point when the decoder is supposed to begin decoding it.

Both are usually specified in units of the frame rate. Since the pts & dts are frame parameters and the VUI is a stream parameter, I don't they are directly related, except that the denominator is likely signaled in some way.

    I tried to create a user account on bitbucket so I could have
    issue 21 assigned to me but I keep getting


BB might not allow issues to be assigned to users who don't have push access anyway, so don't be too concerned about this. You can add a comment to the issue stating you are working on it. Patches should go through this mailing list anyway.

--
Steve


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I think the denominator that you are looking for is already set in class TimingInfo. vui_num_units_in_tick(confusingly named, if I understand it correctly) and vui_time_scale are set based on frame rate. The other TimingInfo members that are not set depend on the consistency of timing of the frames.

One other possibility is the hrd parameter m_tickDivisorMinus2. It is set to 100 - 2 in TComSPS::setHrdParameters though given the description of tic_divisor_minus2 in the spec I am not sure if this is an accurate or useful value.

Since it looks like currently no VUI is generated, perhaps I should just add what's needed so a VUI can optionally be added to an encoded video along with filling out the rest of the VUI's fields.
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