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| -rw-r--r-- | notes.md | 39 |
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@@ -48,3 +48,42 @@ Which file to include: | `suseconds_t` | `<sys/types.h>` | signed | | `clock_t` | `<sys/types.h>` | could be float | | `time_t` | `<sys/types.h>` | signed | + + +Here's my reading of the lowest-bitrate possible for our HDMI sink: + +HDMI v1.4 (2009/06/05) § 6.2.1 "Format Support Requirements" + +> - An HDMI Source shall support at least one of the following video +> format timings: +> + 640x480p @ 59.94/60Hz +> + 720x480p @ 59.94/60Hz +> + 720x576p @ 50Hz +> … +> +> - An HDMI Sink that accepts 60Hz video formats shall support the +> 640x480p @ 59.94/60Hz and 720x480p @ 59.94/60Hz video format +> timings +> +> - An HDMI Sink that accepts 50Hz video formats shall support the +> 640x480p @ 59.94/60Hz and 720x576p @ 50Hz video format timings. + +These latter 2 requirements match what is in CEI-861-D §3.1 "General +Video Format requirements" Table 1. + +I'm a little confused about the 50Hz systems requirement; if it +needs to support 640x480@60Hz, does that mean that it's *also* a 60Hz +system and must therefore also support 720x480@60Hz? + +Anyway, I need to support at least 640x480p@60Hz and 720x480@60Hz, and +it would be nice to support 720x576p@50Hz. Note that PicoDVI supports +these first two, but not the @50Hz one. + +| format | bitrate | +|---------------|-----------------------| +| 640x480p@60Hz | 18,432,000 pixels/sec | +| 720x480p@60Hz | 20,736,000 pixels/sec | +| 720x576p@50Hz | 20,736,000 pixels/sec | + +https://forums.parallax.com/discussion/download/128730/Hdmi-1.4-1000008562-6364143185282736974850538.pdf +https://ia803002.us.archive.org/1/items/CEA-861-D/CEA-861-D.pdf |