Encoding of videos for mastering is driven by quality. The objective is to achieve a video file that adheres to strict industry standards.
Usually, a single or a series of masters are created to be to be replicated or to be used as sources in making copies of the video to other formats.
As an example, a video master for a DVD is created with a professional MPEG-2 video encoder from a video tape (a master video tape itself, usually.) Great attention is placed on creating a pristine, free of artifacts MPEG 2 file that goes through a quality control process (QC) by a human that watches the video in a room equipped with video monitors that have been calibrated for color, brightness, etc. The QC process also involves looking at the video signal on a waveform monitor and vector scope to verify its integrity. There are also QC software programs that can analyze the file for anomalies in the stream.
It is not uncommon that file candidates to be masters are rejected. Video material varies greatly and that makes the video encoding for masters challenging. Parameters in mastering type video encoders can be adjusted for scenes with fast motion, noise, or scene changes. Some encoding packages allow the encoding operator to adjust these parameters on a scene by scene basis. And as you can imagine, this process becomes very time consuming.
A good video mastering workflow is illustrated in the figure below.
Usually, a single or a series of masters are created to be to be replicated or to be used as sources in making copies of the video to other formats.
As an example, a video master for a DVD is created with a professional MPEG-2 video encoder from a video tape (a master video tape itself, usually.) Great attention is placed on creating a pristine, free of artifacts MPEG 2 file that goes through a quality control process (QC) by a human that watches the video in a room equipped with video monitors that have been calibrated for color, brightness, etc. The QC process also involves looking at the video signal on a waveform monitor and vector scope to verify its integrity. There are also QC software programs that can analyze the file for anomalies in the stream.
It is not uncommon that file candidates to be masters are rejected. Video material varies greatly and that makes the video encoding for masters challenging. Parameters in mastering type video encoders can be adjusted for scenes with fast motion, noise, or scene changes. Some encoding packages allow the encoding operator to adjust these parameters on a scene by scene basis. And as you can imagine, this process becomes very time consuming.
A good video mastering workflow is illustrated in the figure below.
To avoid storing RGB or YUV files, some facilities and studios have been creating high quality compressed files like MPEG-2 @ 50Mbs I frame only to be stored and used as masters to create other files down stream. They call them “mezzanine” files as they are an intermediate master in the creation of other videos. These mezzanine files should also follow the same type of workflow as they are a master on their own. Mezzanine files are being used today to create podcast, streaming files for web delivery in many formats as FLV, H.264, WMV or several flavors of Quicktime. The great advantage of using a mezzanine file as the source is that the encoding of new target files can be automated, and managed by a computer. Also, it uses less bandwidth on the network as compared to uncompressed videos or using tapes as sources.
In my opinion, H.264 should be used to create mezzanine files as greater video quality can be obtained while producing smaller files.
Next post will cover transcoding automation
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