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software:sony-vegas-pro

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This information is for Sony Vegas Pro 10, but much of it will also apply to Vegas Pro 11 and 12.

Color Space

  • Vegas Pro's working color space is RGB with a range of 0-255 in each of the R, G, and B channels.
  • In different places in the Vegas UI, the same full range is shown with a scale of 0-255, 0-1, or 0-100.
  • In 8-bit projects, RGB values are integers 0-255.
    • 8-bit mode is quite fast for editing, preview, and rendering.
  • In 32-bit projects, RGB values are 32-bit floating point values.
    • 32-bit mode is quite slow for editing, preview, and rendering.
    • 32-bit mode is more accurate and less prone to banding and other color precision artifacts - especially the cumulative errors of long filter chains.
    • 32-bit projects support values below 0 and above 255, and some filters allow access to these out-of-range values. For example, increasing the contrast could push a low value below 0, and decreasing the contrast could bring a below-0 value back above 0.
    • Compositing operates with 32-bit floating point precision in 32-bit projects.
    • Filters and media generators with green icons operate with 32-bit floating point precision in 32-bit projects; filters and media generators with a blue icon support only 8-bit integer precision.
    • In 32-bit full range projects, you should set the compositing gamma to 2.22, which means that Vegas's compositing and filters operate linearly on the encoded RGB values, same as in 8-bit and 32-bit video levels projects. Setting the compositing gamma to 1 changes the behavior of compositing and some filters in a way that you probably don't want (but perhaps is appropriate for video sources with a linear transfer function).
  • Projects can be switched freely between 8-bit mode, 32-bit video levels mode, and 32-bit full range mode, but filters may behave differently depending on how your input formats are mapped to RGB level ranges.
  • By default Vegas Pro makes no particular assumptions about the primary chromaticities or transfer function (“gamma”) of the RGB encoding: operations are linear on the RGB values, and the scopes and preview window show the full range of RGB values with no conversion or remapping.

Monitor Calibration

  • Typically your source video and delivery formats will be rec.709-encoded, so ideally your monitor should be calibrated to display rec.709 video as well.
  • Most computer monitors are calibrated for sRGB, which is very close to rec.709. They have the same primary chromaticites and white point. Rec.709's transfer function is approximately a power curve with a gamma of 2.4, compared to sRGB's transfer function which is a power function with a gamma of 2.2. The differences are small enough that you'll be fine to just calibrate your monitor for sRGB and ignore the differences - in fact the gamma would need to be changed by a larger amount than this small difference to account for different levels of ambient light in your editing environment.
  • I suggest calibrating your monitor using the excellent Lagom LCD test pages, even if you use a CRT or other type of monitor.
    • Ise the Contrast page:
      • Set your monitor's contrast adjustment to the maximum, and then adjust the monitor's brightness and the individual R, G, and B gain and bias settings.
      • Make black, grey, and white appear with no tint.
      • Make the black background as dark as possible while still showing even contrast across each of the color ramps. There should be a visible difference in brightness between the black background and the leftmost rectangle of each gradient. As much as possible, the changes in apparent brightness from each rectangle to the next should be equal at every position in each gradient and between the gradients.
    • Use the Black level and White saturation pages to fine tune the black level, white level, and color balance. There should be a visible difference between every level.
    • Use the Gamma calibration page to adjust the gamma. Aim for a gamma between 2.2 and 2.4. Most good monitors calibrated for sRGB will be right around 2.2 out of the box. If your monitor doesn't have a gamma adjustment, your video card driver might, but beware that it might have separate color adjustments for 2D, 3D, and video surfaces. It's best to not change the gamma if you don't have to. An adjustment of the monitor's brightness adjustment is usually all that's needed to account for different ambient light conditions in your editing environment.

Level ranges and input/output conversion

  • By default, most operations in Vegas use the full 0-255 range of RGB values regardless of the project settings:
    • preview window
    • compositing
    • filters
    • still image import
    • media generators
    • full-screen preview (unless you enable the Studio RGB option in prefs, which uses 16-235)
    • Vectorscope (unless the Studio RGB option is selected, which uses 16-235)
    • Waveform scope (unless the Studio RGB option is selected, which uses 16-235)
    • Histogram (the Studio RGB option has no effect. It seems to be a bug)
    • RGB Parade (the Studio RGB option has no effect. It seems to be a bug)
  • Video input mapping to RGB level ranges, and video output mapping from RGB level ranges depends on the video format and the project setting. OOR means out-of-range preservation - that is, values above the channel's maximum and below the minimum are preserved (including superwhites and superblacks).
8-bit project
RGB levels / OOR
32-bit video levels
RGB levels / OOR
32-bit full range
RGB levels / OOR
YCbCr↔RGB
conversion matrix
.MP4 h.264 input 16-235 / yes 16-235 / yes 0-255 / yes rec.709
.MTS h.264 input 16-235 / yes 16-235 / yes 0-255 / yes rec.709
.MOV h.264 input † 0-255 / no 0-255 / no 0-255 / no rec.601
.MOV ProRes input † 0-255 / no 0-255 / no 0-255 / no rec.709
.MOV Cineform input 16-235 / yes 16-235 / yes 16-235 / yes rec.709
.AVI Cineform input 16-235 / yes 16-235 / yes 16-235 / yes rec.709
Mainconcept MPEG-2 output16-235 / yes16-235 / yes 0-255 / yes rec.709
Mainconcept AVC/MP4 output16-235 / yes16-235 / yes 0-255 / yes rec.709

† Quicktime h.264 and ProRes input boost the gamma by 1/0.88. Compensate by adding a Levels filter with 0.88 gamma (and no changes to the input and output limits) at the beginning of the filter chain. It is a documented bug in Quicktime:

  • So yes, Vegas's handling of RGB levels is totally inconsistent and non-standard. You'll need to do different things in your project depending on your input and output formats, project settings, and preferences.
  • A levels filter with the “Studio RGB to Computer RGB” preset expands RGB levels from 16-235 to 0-255.
  • A Levels filter with the “Computer RGB to Studio RGB” preset compresses RGB levels from 0-255 to 16-235.
  • Mapping from input format ranges and mapping to output format ranges depends on the format, and here Vegas seems to follow standards:
    • 8-bit YCbCr: Y=16-235, Cb=16-240, Cr=16-240
    • 10-bit YCbCr: Y=64-940, Cb=64-960, Cr=64-960
    • 8-bit RGB: R=0-255, G=0-255, B=0-255
  • Quicktime .MOV input requires Quicktime to be installed. I use Quicktime Alternative 3.2.2.
  • Vegas can read .AVI Cineform and .MOV Cineform formats with 10-bit precision, thank to integration with the Cineform SDK. Install the free GoPro Studio to get codecs that enable reading and writing of Cineform files. (GoPro Studio version 2.0.0.285 tested)
  • If Vegas is reading your input using the wrong YCbCr→RGB conversion matrix, you can compensate by using 601<->709 Channel Blend filter values at the beginning of your filter chain.
  • If your output renderer allows out-of-range values, prevent out-of-range values by adding a Curves filter to the output: the default curve clips values below 0 and above 255. To clip values below 16 and above 235, add a “Studio RGB to Computer RGB” levels filter, then a default curve, then a “Computer RGB to Studio RGB” levels filter.

Settings & Switches

  • Resampling of video events means that frame blending will be used when the event frame rate doesn't match the output frame rate. If the difference is tiny, e.g. 30 fps to 29.970 fps, you probably want to disable resampling so that frames are not blended. Same for integer ratios, e.g. 60 fps to 30 fps.

Workflow Tips

  • Video filters may be applied to source media, the timeline video events, video tracks, or to the video output (tools menu, video, output FX).
  • While editing, set the project to 8-bit mode and reduce the project resolution to match your full-screen preview device. This will make preview of filter adjustments much more responsive. Don't forget to change the project resolution back when you render.
  • To apply the same filter settings to multiple events,
software/sony-vegas-pro.1381176110.txt.gz · Last modified: 2013/10/07 20:01 by balazer