On Thu, 1 Feb 2007 Dan Streetman wrote:
> Ick, it's the 4:2:0 chroma sampling, I believe. Why oh why doesn't > HDV use 4:1:1 or 4:2:2? > Without being any expert on this, my understanding is that 4:1:1 color sampling as used in NTSC DV25, is considered to be a bad format to transcode to MPEG-2 for DVD video disks, which do use 4:2:0. This misalignment of color samples results in a final 4:1:0 color space or only 12,5 percent of the original chroma information (this problem doesn't exist in PAL DV25 which itself also applies 4:2:0 color sampling) according to: http://www.humanvalues.net/hdv/#dv25 4:2:0 sampling format and 8 bit quantization used for HDV in general, does for HDV 1080i or MPEG-2 [EMAIL PROTECTED] occopy the maximum 25 Mbit/s bitrate to be recorded on miniDV tapes ..... http://en.wikipedia.org/wiki/HDV#Specifications http://www.expandore.com/product/Sony/Proav/model/HDV/QNA.htm#HDV%20Specifications 4:2:2 as used in MPEG-2 [EMAIL PROTECTED] is "bitrated" at 80 Mbit/s ans is (was) examplified for "potential future MPEG-2 based HD products from Sony and Panasonic". http://en.wikipedia.org/wiki/MPEG-2#Profiles_and_Levels And at the same time two questions I myself have been wondering about looking in the last table: Q1) Maybe someone here can explain what makes the difference between HDV 1080i at 25 Mbit/s and its MPEG-2 profile [EMAIL PROTECTED], which is tabeled to use 60 Mbit/s below Q2) And at the same time as I myself have been searching for a better Analog->Digital video converter than just DV25/1394 with the limited bitrate and color space 4.1:1: Shouldn't a converter using the MPEG-2 profile [EMAIL PROTECTED] with 720x576(480) resolution, 4:2:2 color space and bitrate >= 25 Mbit/s over 1394 have the potential for a better result than DV25? Terje J. Hanssen _______________________________________________ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
