Encoding Strategy v0.1

[CraigWatt]

/* What each alias should represent - handy table
CODEC BITS COLOR_SPACE CAN_MAX_RES CAN_MIN_RES ALIAS_MAX_RES ALIAS_MIN_RES ALIAS_NAME
av1 - 10 bit - unspecified AND bt709 - 4k max -
av1 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 1080p max - 240p min -

  vp9 -   10 bit - unspecified AND bt709 AND bt2020? -                            4k max -              
  vp9 -   10 bit - unspecified AND bt709 AND bt2020? -                            1080p max -           
  vp9 -   10 bit - unspecified AND bt709 -                                        4k max -              
  vp9 -   10 bit - unspecified AND bt709 -              ∞ -          240p min -   1080p max -    240p min -

  hevc -  10 bit - unspecified AND bt709 AND bt2020? -                            4k max -              
  hevc -  10 bit - unspecified AND bt709 AND bt2020? -                            1080p max -               
  hevc -  10 bit - unspecified AND bt709 -                                        4k max -                 
  hevc -  10 bit - unspecified AND bt709 -              ∞ -          1081p min    4k max -       1081p min - 
  hevc -  10 bit - unspecified AND bt709 -              ∞ -          240p min -   1080p max -    240p min -              

  h264 -  8 bit -  unspecified AND bt709 -              ∞ -          240p min -   1080p max -    240p min -           

/*SCALE DOWN BUCKETS */

/* 720p max SDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
h264 - 8 bit - unspecified AND bt709 - ∞ - 240p min - 720p max - 240p min -
hevc - 10 bit - unspecified AND bt709 - ∞ - 240p min - 720p max - 240p min -
vp9 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 720p max - 240p min -
av1 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 720p max - 240p min -
/ 1080p max SDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
h264 - 8 bit - unspecified AND bt709 - ∞ - 240p min - 1080p max - 240p min -
hevc - 10 bit - unspecified AND bt709 - ∞ - 240p min - 1080p max - 240p min -
vp9 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 1080p max - 240p min -
av1 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 1080p max - 240p min -
/ 1080p max HDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
hevc - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 1080p max - 240p min -
vp9 - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 1080p max - 240p min -
/ 4k max SDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
hevc - 10 bit - unspecified AND bt709 - ∞ - 240p min - 4k max - 240p min -
vp9 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 4k max - 240p min -
av1 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 4k max - 240p min -
/ 4k max HDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
hevc - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 4k max - 240p min -
vp9 - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 4k max - 240p min -
/ 8k max SDR support (this does not factor in processor capabilities) ------------------------------------------------------ /
hevc - 10 bit - unspecified AND bt709 - ∞ - 240p min - 8k max - 240p min -
vp9 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 8k max - 240p min -
av1 - 10 bit - unspecified AND bt709 - ∞ - 240p min - 8k max - 240p min -
/ 8k max HDR support (this does not factor in processor capabilities) ------------------------------------------------------ */
hevc - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 8k max - 240p min -
vp9 - 10 bit - bt2020? CANDIDATES ONLY - ∞ - 240p min - 8k max - 240p min -

/SCALE UP BUCKETS/
/* if a candidate file can never be in a higher bucket,
'Can only ever be' BUCKETS - bottom up

h264 'only ever be' buckets --->
   *h264 processor*
   *720p tv*
   *SDR MAX tv*
     /* 240p to 720p - unspecified - h264-8bit OR 10bit - CANDIDATES ONLY ---------- */
     /* 240p to 720p - bt709 - h264-8bit OR 10bit - CANDIDATES ONLY ---------- */
     /* 240p to 720p - bt709 - h264-8bit OR 10bit - POSSIBLE TRANSFORMS ONLY ---------- */
 
   *h264 processor* 
   *720p tv*
   *HDR MAX tv* - VERY UNLIKELY POSSIBILITY IMO
     /* 240p to 720p - bt2020? - h264-10bit - CANDIDATES ONLY ---------- */
     /* 240p to 720p - bt2020? - h264-10bit - POSSIBLE TRANSFORMS ONLY ---------- */
 
   *h264 processor*
   *1080p tv*
   *SDR MAX tv*
     /* 721p to 1080p - unspecified - h264-8bit OR 10bit - CANDIDATES ONLY ---------- */
     /* 721p to 1080p - bt709 - h264-8bit OR 10bit - CANDIDATES ONLY ---------- */
     /* 721p to 1080p - bt709 - h264-8bit OR 10bit - POSSIBLE TRANSFORMS ONLY ---------- */

   *h264 processor*
   *1080p tv*
   *HDR MAX tv*
     /* 721p to 1080p - bt2020? - h264-10bit - CANDIDATES ONLY ---------- */
     /* 721p to 1080p - bt2020? - h264-10bit - POSSIBLE TRANSFORMS ONLY ---------- */

hevc 'only ever be' buckets --->

*hevc processor*
*720p tv*
*SDR MAX tv*
  /* 240p to 720p - unspecified - hevc-8 OR 10bit - CANDIDATES ONLY ----- */
  /* 240p to 720p - bt709 - hevc-8 OR 10bit - CANDIDATES ONLY --------- */
  /* 240p to 720p - bt709 - hevc-8 OR 10bit - POSSIBLE TRANSFORMS ONLY --------- */

*hevc processor*
*720p tv*
*HDR MAX tv* - VERY UNLIKELY POSSIBILITY IMO
  /* 240p to 720p - bt2020? - hevc-10bit - CANDIDATES ONLY ---------- */
  /* 240p to 720p - bt2020? - hevc-10bit - POSSIBLE TRANSFORMS ONLY ---------- */

*hevc processor*
*1080p tv*
*SDR MAX tv*
  /* 721p to 1080p - unspecified - hevc-8 OR 10bit - CANDIDATES ONLY ---------- */
  /* 721p to 1080p - bt709 - hevc-8 OR 10bit - CANDIDATES ONLY ---------- */
  /* 721p to 1080p - bt709 - hevc-8 OR 10bit - POSSIBLE TRANSFORMS ONLY ---------- */

*hevc processor*
*1080p tv*
*HDR MAX tv*
  /* 721p to 1080p - bt2020? - hevc-10bit - CANDIDATES ONLY ---------- */
  /* 721p to 1080p - bt2020? - hevc-10bit - POSSIBLE TRANSFORMS ONLY ---------- */

*hevc processor*
*4k tv*
*SDR MAX tv*
  /* 1081p to 4k - unspecified - hevc-8 OR 10bit - CANDIDATES ONLY ---------- */
  /* 1081p to 4k - bt709 - hevc-8 OR 10bit - CANDIDATES ONLY ---------- */
  /* 1081p to 4k - bt709 - hevc-8 OR 10bit - POSSIBLE TRANSFORMS ONLY ---------- */

*hevc processor*
*4k tv*
*HDR MAX tv*
/* 1081p to 4k - bt2020? - hevc-10bit - CANDIDATES ONLY ---------- */
/* 1081p to 4k - bt2020? - hevc-10bit - POSSIBLE TRANSFORMS ONLY ---------- */

vp9 'only ever be' buckets --->
av1 'only ever be' buckets --->

[CraigWatt]

just leaving this here as it might be useful for aiding in understanding extraction of color data of video files (especially for aiding in differentiating between HDR10, HDR10+ and DOLBY VISION, as this currently isn't super clear to me yet.

https://codecalamity.com/encoding-uhd-4k-hdr10-videos-with-ffmpeg/

Another appropriate task that will tie in nicely with #9 and #30 is to establish the key differences between ffprobe of HDR10, HDR10+ and DOLBY VISION video files are by doing so with appropriate test variables.

This will help define scenarios better for vfo. I think right now vfo is relying heavily on bt2020nc to simply detect HDR, instead of a specific 'type' of HDR.

[CraigWatt]

• Retain Source whenever possible

• Encode to Highest Quality (for device scenario) whenever possible

• Avoid unnecessary duplicates (remuxes)

Side Note: There may be scenarios where we WANT to encode an exact match candidate 'down' to a lower bitrate... But for now we aren't necessary specifying 'max bitrate/peak bitrate' for alias's yet. So this can remain a future consideration.

For now we can 'cheat' and say we are in the business of retaining quality as per video codec. We are assuming that when remux occurs, processor will be able to handle the bitrate.

This puts us in higher chance of danger IF the original/source version has an extremely high bitrate for a older video codec (h264, mpeg-2) but again, let's roll the dice for now.