GoPro Studio 2 User Manual

							GoPro Studio 2.5 User Manual 
APPENDIX B: THE GOPRO CINEFORM CODEC 
 
Compression  
 
Video file formats use standard wrappers like AVI, QuickTime (MOV )or  MXF to ensure broad playback compatibility with numerous video 
applications. W ithin the AVI or MOV wrapper, the underlying file might be compressed (or uncompressed) using various codecs, all of which 
guarantee compatibility with a calling application thr ough OS-recognized AVI or QuickTime interfaces. The primary function of a codec is to ensure 
that the decoded image best represents the original uncompressed source—within the inherent constraints of the chosen codec and the 
parameters selected during the  encode (or compression) operation.  
  Traditional Codec (Encoder-Decoder) Functions  
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Codec designs are many, as are the resulting visual fidelity and CPU requirements that result from various designs. As a general rule, most 
codecs have been designed for eit her acquiring images or video inside a camera (JPEG, DV, DVCPRO, AVCHD, DNxHD) or for distribution 
(MPEG, h.264).  
 
CineForm has taken a different approach with its compression engine,  instead designing a compression subsystem specifically optimized for the 
needs of post -production, and with the inclusion of many system features. T here is a codec at the heart of CineForm’s compression subsystem, 
but the codec is surrounded by additional processing engines that operate underneath the AVI/MOV interface layers through which calling 
applications access compressed data. This allows CineForm’s compression subsystem to perform myriad system -level features difficult to 
otherwise implement.  
  CineForm Compression Subsystem Architecture 
 
   
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Following are the major com ponent pieces in a CineForm compression subsystem:  
 
CineForm Wavelet Codec:  The design goals for CineForm’s codec were:  
  1.  Maintaining extremely high visual fidelity through a rigorous multi -generation post -production workflow, including high bit precision,  
yielding high signal -to -noise ratio.  
2.   Offering extremely fast performance on Intel architecture CPUs such that multiple streams can be processed in real time without the need 
for specialized hardware.  
 
The design characteristics of the GoPro CineForm  codec  are the following:  
 
Transform:  Full-frame Wavelet. “Full -frame” means the entire image is transformed without breaking the image into “blocks” which are the basis 
for DCT -style transforms (JPEG, MPEG, AVCHD, etc .), and which provide the ubiquitous artifact s often visible in complex image sequences. 
CineForm’s full -frame Wavelet transform cannot suffer from these DCT image degradations.  
Chroma Formats and I/O Bit Depth:  10-bit YUV, 12 -bit RGB(A), and 12- bit CineForm RAW 
Spatial Resolution:  Unrestricted 
Bit R ate: Variable (constant quality)  
Encoder Quality Settings:  6 (user selectable)  
Symmetry:  Symmetric (similar speed for encoding and decoding)  
Multi -Resolution Decoding:  Wavelet algorithms offer a valuable feature for use in playback or other post -production  applications : the ability to 
decode a full -resolution image to a lower resolution. Specifically the ability to decode to ½ or ¼ resolution in each dimension is allowed,  while 
using less CPU load compared to a full -resolution decode. CineForm software dynamically  takes advantage of this characteristic during editorial.  
Performance:  Function of CPU speed and memory bandwidth, but below are representative examples run on a 3.2GHz Intel Corei7 (single chip 
quad core):  
 
10 bit 1920×1080 4:2:2 232 fps 
12 bit 1920×1080 4:4:4 (CineForm 444) 104 fps 
12 bit 4096×2048 4:4:4 (playback at 2K) 52 fps 
12-bit 4096×2048 4:4:4 (playback at 4K) 20 fps 
Relative Performance ( versus JPEG2000): CineForm compression ranges from around 5X to 10X faster than JPEG2000. Co mpression 
performed by CineForm in an hour may take up to 10 hours for JPEG2000 to perform on the same imagery.  
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Visual Quality (versus HDCAM SR):  CineForm visual fidelity routinely exceeds that of the respected HDCAM SR format which is a mainstay in 
professional  production and post -production.  
Read additional quality analysis versus HDCAM SR on StEM test footage…. 
Visual Quality (versus HDV and DVCPRO HD):  CineForm visual fidelity substantially exceeds that of most camera compression formats such as 
HDV, DVCPRO HD, AVCHD, etc.  
Temporal/Spatial Transform Engine:  The Transform Engine allows source and output formats to be different than the compressed format, in 
either spatial resolution or chroma format.  
Spatial  Transforms:  CineForm spatial processing is unrestricted and handles all standard resolutions: SD, HD, 2K, 4K and beyond.  
Color Space Transforms:  Color space transforms can move images between RAW, 4:2:2 and 4:4:4 chroma in real time. Transforms are always 
performed using floating- point arithmetic to preserve color accuracy. When decoding from CineForm RAW sources, CineForm’s demosaic 
algorithms are performed in real time.  
Active Metadata Processing Engine:  CineForm’s Active Metadata Processor allows numerous non- destructive operations to be performed on 
image frames after decompression including color processing (white balance, gain/offset, gamma, saturation, RGB matrix controls, 3D LUTs and 
more), image flip, 3D processing and more.  
   
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Active Metadata™ Technology Overview  
 
Video file formats use standard wrappers like AVI, QuickTime (MOV) or MXF to ensure broad playback compatibility with numerous video 
applications. A calling application requests frames from AVI/MOV files which are in turn decoded and presented to the calling application similar to 
the diagram below. Within the AVI or MOV wrapper, the underlying file might be compressed (or uncompressed) using various cod ecs, all of which 
guarantee compatibility with a calling application through OS -recognized AVI or QuickTime interfaces.  
 
Traditional request by a calling application to “play” (or decode) a compressed file.  
 
   
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Using its  Active  Metadata™  architecture CineForm extends traditional codec -only capability into a full -featured image development subsystem, 
including:  
 
•  Combining “active” processing of decoded images with metadata based on user -established rules. Active processing allows non-
destructive image development including color (White Balance, color matrix, 3D LUTs, etc .), 3D editorial and playback, stream -specific 
information and framing controls  
•   Metadata storage is inside the video essence within user data fields compatible with AVI/MOV files  
•   Active Metadata is compatible with all CineForm file types: 10- bit YUV, 12-bit RGB, 12 -bit RAW and  stereo (3D) 
•   Cross -platform (Win/Mac) and cross -applications compatibility. Active Metadata is transparent to a calling application because all Active 
Metadata processing occurs within the CineForm Image Development Subsystem, prior to presenting the images to the calling application.  
 
 
When a CineForm AVI or MOV file is created, active and/or passive metadata may be inserted into the file. In all cases a Glob ally Unique Identifier 
(GUID) is inserted into the file, plus the encoder curve used when the file  was created. If available, Timecode is written into a Passive Metadata 
field.  
 
The GUID provides a lookup address into the CineForm Active Metadata Database file used during playback.  
 
The encoder curve is included to establish the inverse curve necessary  to return to linear light upon decode.     
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The following are a few examples of Active Metadata insertion into GoPro  CineForm AVI/MOV files: 
 
•  When recording to disk during live capture using a Silicon Imaging camera, white balance and 3D LUT information is w ritten into the 
CineForm RAW file.  
•   When performing disk -based conversions from R ED R3D files, white balance information from the R ED metadata fields is extracted from 
the R ED SDK and written into the CineForm file (YUV, RGB, or CineForm RAW) as Active Metadata.  
•   When a stereo (3D) CineForm file is created, the second stream is stored as Active Metadata, plus other optional fields.  
 
GoPro CineForm Studio allows for: 
 
•  Modifying Active Metadata. Active Metadata created at source file origination always resides inside the file and can never be  modified. 
Modifications to Active Metadata are stored in CineForm’s Active Metadata Database file. GoPro CineForm Studio allows a user to revert 
to the source metadata regardless of future metadata modifications within the Studio application.  
•   Setting Global Playback controls. You can define for playback that all, none or only a portion of the Active Metadata should be applied 
upon decode. A couple examples of when this is useful:  
o   During editorial with CineForm files , the editor may have used Active Metadata color to establish look -intent. But when rendering 
from a CineForm file to DPX files a choice might be made to only apply white b alance and not apply the color look-intent used 
during editorial with Active Metadata.  
o   During 3D playback, global playback controls allow the user to choose whether to play a CineForm stereo file as 2D (either Left 
eye or Right eye), or as one of four diff erent 3D presentation formats (side-by-side, over -under, field interlace or anaglyph).  
•   Defining the rules for applying CineForm’s numerous demosaic algorithms for CineForm RAW content during playback or rendering.  
 
When a calling application requests playb ack of a CineForm file, the Active Metadata processor computes the final output based on user -defined 
global playback rules,  plus individual Active Metadata fields.  
 
 
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