Apple ProRes: Difference between revisions
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| align="center" | High Quality (HQ) || align="center" | 'apch' || align="center" | 220 Mbps | | align="center" | High Quality (HQ) || align="center" | 'apch' || align="center" | 220 Mbps | ||
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ProRes algorithm is based on the [[Discrete_Cosine_Transform | Discrete cosine transform]] (further DCT) and utilizes the following compression techniques: | |||
* custom hybrid [[Golomb|Golomb-Rice]] / [http://en.wikipedia.org/wiki/Exponential-Golomb_coding Exponential Golomb] coding for DCT coefficients | |||
* [[Run_Length_Encoding|run-lenght coding]] | |||
* [[Differential_Coding|differential coding]] | |||
* [[Scalar_Quantization|scalar quantization]] |
Revision as of 14:49, 30 September 2010
- FourCCs used to indicate different ProRes flavours in the QuickTime container:
- Apple ProRes 422 High Quality: 'apch' ('hcpa' in little-endian)
- Apple ProRes 422 Standard Definition: 'apcn' ('ncpa' in little-endian)
- Apple ProRes 422 LT: 'apcs' ('scpa' in little-endian)
- Apple ProRes 422 Proxy: 'apco' ('ocpa' in little-endian)
- Apple ProRes 4444: 'ap4h' ('h4pa' in little-endian)
- Company: Apple
- Whitepaper: http://images.apple.com/finalcutstudio/resources/white_papers/L342568A_ProRes_WP.pdf
- New Whitepaper introducing ProRes LT/Proxy/4444: http://images.apple.com/finalcutstudio/docs/Apple_ProRes_White_Paper_July_2009.pdf
- Samples: http://samples.mplayerhq.hu/V-codecs/HCPA/
ProRes Introduction
Apple ProRes is a family of video codecs used for storing and editing high definition video data in Apple's Final Cut Pro. Apple's official whitepaper lists the codec's key features as being:
- intra-only codecs
- 4:2:2 / 4:4:4:4 source material
- 10-bit (12-bit for ProRes 4444) sample depth
- variable bitrate
Technical documentation on ProRes 422 Standard Definition / High Quality codec
ProRes 422 SD/HQ is the same codec operating on two different bitrates (flavours). Two different FOURCCs are used in order to indicate each flavour:
Flavour name | FOURCC | Bitrate |
---|---|---|
Standard Definition (SD) | 'apcn' | 145 Mbps |
High Quality (HQ) | 'apch' | 220 Mbps |
ProRes algorithm is based on the Discrete cosine transform (further DCT) and utilizes the following compression techniques:
- custom hybrid Golomb-Rice / Exponential Golomb coding for DCT coefficients
- run-lenght coding
- differential coding
- scalar quantization