[MEncoder-users] compression: 1080i versus 720p

[Andrew Berg]

On 12/20/2009 12:42 PM, RC wrote:
> Interlaced video is measured in fields.  NTSC is 60Hz (PAL is 50Hz) or
> 60 fields per second.
Right, but 60 half-height fields contain the same amount of data as 30
full height frames, do they not? Deinterlacing does not reduce the
amount of data. In fact, certain algorithms /increase/ the amount of
data by turning 60 fields into 60 frames. Some codecs (e.g. x264) are
not able to compress interlaced material as well as they compress
progressive material, but it's the same amount of data.