HD Video for the Web - Guide for Vegas Users

HD Video for the Web – the Sony Vegas Pro Perfectionist’s Guide

Purpose: To document procedures for Sony Vegas users to transcode Hi-def source video for high quality web delivery.

Contents:

Comments & Discussion
Summary
Background
Tutorials
Sample Videos
Credits

Comments & Discussion: Should be posted here: Vegas to Youtube, Vimeo, Web -- A New Look

Summary:

The Levels Issue
- Most modern PC players, including all web-based delivery tested, expect 16-235 and map it out to 0-255 summarily, whether the video needs it or not. This is completely irrespectful of the codec used. None of these players or services do a levels analysis pass (yet) on YUV source. They do a blind, dumb correction instead.
- Most amateur video, the vast preponderance of what is uploaded to the internet for viewing and / or download, IS NOT SHOT IN A CONTROLLED 16-235 SPACE. This is very important to understand. Much (most?) of it is clipped at 255 already. Recommending that it come back clipped even more as a result of doing nothing is not good advice.
- It is unfortunate, but most amateurs who override autoexposure controls, do so in order to see an image on their camera LCD displays in bright sunlight. The common word for this practice is "clipping."
- The vast majority of amateurs do not have access to video scopes, nor do they care. In most cases, applying a stock Studio RGB correction ensures exactly what they shot is what they get back in playback or web delivery, whether right or wrong, but not for better or worse. Even in the cases where blacks are not initially all the way down to 0, applying the correction is subjectively better than none at all, because the human eye naturally gravitates to the highlight details, not the shadows.
- The people who should NOT be following that stock advice include:
  - Professionals who already conform their levels to REC 601/709 [corrected for contextual reasons], or those who render full RGB and do not intend to view their video on consumer or browser software players.
  - Amateurs who stick with rendering WMV or amateur Quicktime formats. None of the tutorials here have recommended those as delivery formats, and it is well known that some amateur codecs do their own internal conversion, often unpredictably or to the detriment of normal playback methods.
  - In any event, it is important to understand that it is not recommended to apply a stock Studio RGB correction to video that is already conformed to 16-235, or in the few cases where the local PC is not showing the expected levels expansion. I am not convinced that the relative sliver of cases where these conditions exist somehow trumps the majority of situations.

The Rendering Engine

Two separate workflows have been developed. Both offer 3 common advantages
- Superior deinterlacing to the simple blend or interpolate available in Sony Vegas, or indeed other plugins available in Vegas such as Yadif or Smart Deinterlace
- Superior resizing to Sony Vegas. i.e. Lanczos3 instead of Vegas Pro's bicubic algorithm
- Superior H.264/AVC encoding to Sony Vegas
The Sony Vegas Pro->DNxHD->HandBrake workflow
- Why HandBrake?
  - Assuming the target render is 1280x720 30p h.264 .mp4, an excellent resizing and deinterlacing method is required.
  - HandBrake was chosen because:
    - It uses the Lanczos 3 resizing algorithm
    - Quality, selective deinterlacing is via "Decomb" Video filter.
    - Tests have confirmed the visual quality surpasses both the MainConcept AVC/AAC & Sony AVC encoders available in Sony Vegas - particularly and lower bitrates.
    - Particularly in the CQ, Constant Quality mode, HandBrake renders very quickly.
    - HandBrake is free, Open Source software. Available here
  - Why the Avid DNxHD intermediate?
    - It is one of the few intermediate codecs that is fully compatible with Handbrake.
    - It is visually lossless, relatively fast to render, and produces small files
    - It works on all platforms and OS.
    - The DNxHD Codec is freely available from Avid here. Be sure to select the 2.3.7 download, not an older one. Available here
- The Sony Vegas Pro->Debugmode Frameserver->AviSynth/QTGMC->MeGUI/Nero-AAC/x264 Workflow:
  - Why MeGUI/Nero-AAC/x264?
    - MeGUI is a graphical user interface for many video processing tools. We are using it as a GUI for the x264 video encoder, the Nero AAC audio encoder, and for muxing the final .mp4 file.
    - Nero AAC is a free, high quality AAC audio encoder. It gives a very good quality:bitrate ratio. It avoids bugs that we have found when uploading FAAC or LAME mp3 audio to YouTube
    - x264 is a free, high quality H.264/AVC encoder. It is very actively developed, highly configurable, and provides a high quality:bitrate ratio. It consistently wins codec comparisons such as this: http://compression.ru/video/codec_comparison/h264_2010/
  - Why Debugmode Frameserver?
    - Debugmode Frameserver is a free program for transferring video from one application to another on demand without the need to render a large intermediate file. We will use this to transfer your video from your NLE to AviSynth
  - Why AviSynth/QTGMC?
    - AviSynth is another frameserver which allows advanced processing of video files. We use it as the environment to deinterlace and resize the video, to adjust levels if necessary, and to pass video to MeGUI.
    - QTGMC is a script that uses a number of AviSynth filters together to deinterlace video, but simplifies their use by presenting straightforward presets and settings. It provides state-of-the-art software deinterlacing but can be rather slow.

Background: Discussion of various procedures to create high quality video clips for web delivery have been extensively discussed on the Sony Creative Software–Vegas Pro forum

Fall 2009: “Laurence” posed the question, “Does anyone know the proper answer of whether an mp4 render used for uploading a video to a service such as Vimeo or Youtube should be at sRGB or cRGB levels?” ref: Youtube/Vimeo/Facebook HD uploads: sRGB or cRGB?
Summer 2010: Forum participant “musicvid” started a discussion to investigate the observation that YouTube uploads perform a sRGB to cRGB color space conversion on uploaded clips – resulting in reduced definition, blown out whites and crushed blacks ref: Youtube Mangles cRGB
During the same time period "musicvid" was investigating the use of the Open Source software, HandBrake to produce high quality video clips with speedy renders. HandBrake performs progressive video renders using the x264 library which streams to the H.264/MPEG-4 AVC format. HandBrake Website
Fall 2010: Much forum discussion centered around the best format Sony Vegas intermediate renders to use as Source Video Files for HandBrake. The free Avid DNxHD codec appeared to be a good solution
- Reference thread: Why does HandBrake look so much better?
- Avid DNxHD Download: Version 2.3.7
Winter 2011: "musicvid" starts a thread to discuss the “Best” method for the Sony Vegas Pro user to transcode AVCHD clips for web delivery: Vegas to Youtube, Vimeo, Web -- A New Look
Winter 2011: While "musicvid" settled on the AVCHD->Vegas->DNxHD->HandBrake->H.264/MPEG-4 route to excellent quality renders, “Nick Hope”, also of the Vegas Pro Forum has developed another route to high quality videos for web delivery: AVCHD->Vegas->DebugMode Frameserver->AviSynth->MeGUI->H.264/MPEG-4 ref: Vegas to the Web for the Videophile - A Tutorial

Tutorials: Two excellent methods of transcoding Hi Def videos for web delivery have been developed:

Musicvid’s Vegas Project (Version 4) for download is located here: VegasProject.zip Caution: it includes all source clips and is a 498MB download

Tutorial video
Vegas-to-Vimeo Tutorial - A Better Method from musicvid on Vimeo.
Future PowerPoint presentation to be inserted here

DNxHD Render Settings

"Laurence" of the Sony Vegas Pro Forum offers this excellent procedure for improved Audio. Discussion is here: Any improvements to Handbrake Audio?

Choose Uncompressed audio in the Sony Vegas Custom DNxHD template
Make sure that Vegas sample rate conversion is set to best (it defaults at "good" which is not).
Make sure that Handbrake is not doing a sample rate conversion (set it to the same sample rate as your Vegas render), and that the format's match (Handbrake wants to do a surround to Dolby Pro Logic downmix unless you tell it not to).

HandBrake Settings