MPEG 4 vs. MPEG 2... what is the difference???

Question

I'm looking at some professional high-definition video cameras - from Sony and Panasonic. The Sony uses MPEG 2, the Panasonic uses MPEG 4 - what is the difference and do I need to consider it when buying my camera? Also, what does the "4:2:0" or "4:2:2" or "4:4:4" (found on only the top cameras?) actually refer to? Thanks to anybody who can give me a decent answer.

Answer 1

Start here:

http://en.wikipedia.org/wiki/Chroma_samp...

If you are looking for best available video quality, MiniDV tape is the storage media of choice. The storage format onto the digital tape is DV (standard definition) or HDV (HighDefinition Digital Video). External hard drives (like the one with the Sony HVR-V1U and those from Firestore) save in DV or HDV format.

If you are looking at the Panasonic HDX200, be aware that the flash memory storage is onto P2 cards - and they require a PCMCIA port on the computer for data file transfer. Most towers (with the most CPU horsepower for rendering high definition video) do not have this sort of slot - and some laptops do... but they seem to be moving in the direction of "Express" card slots... The P2 cards are pretty pricy - I have found that carrying a laptop (Mac PowerBook G4 with PCMCIA slots) is easiest - with two cards for the camera - while one is being used for capturing video, the other is offloading onto the Mac... you will want an external drive (preferably firewire) because the internal drives are not big enough to store the volume of video transferred.

The Sony HVR series (V1U and Z1U) are good, affordable miniDV cams (they both shoot in standard definition DV 4:3 and 16:9 and HDV which is by default 16:9). The Panasonic DVX100B is standard def only - and a great camcorder. For hidef (and standard def) the HVX200 is awesome (but with the P2 cards). I would caution you on the Panasonics, however - you need to go through some hoops on some of the video transfer - standard def 16:9 comes across as letter boxed 4:3.

Since you are in this market - might I suggest that you look at the Canon XHA1... It, and the Sony HVR-V1U, are on my short list at the moment.

When I export HDV projects as data files, I generally use MPEG4 - the quality is better... the compression algorithm is better equipped to keep the clarity of video rendered from HDV than MPEG2 can...

Answer 2

MP2 is the method used for HD digital television. Unlike DV where every frame stands alone, making editing simple, MP2 uses temporal compression, that is it combines a group of frames together. This reduces the bandwidth requirement for HD down to the same data rate as miniDV. MP4 is for IP delivered video, which is file based and does not require synchronized streaming necessary for MP2 or DV. Unlike MP2, which is essentially a government enforced standard, MP4 does not have reliable interchange across codecs of various designs.

The last vestige of analog is for the sample rates specified for digital encoding. In order to insure high quality analog conversion of digital data, the basic luminence component has to be sampled at 4 times the color subcarrier frequency. While subcarrier is not needed for pure digital television, it is the standard for sample rates. The 3 number specification give the samples taken for luminence and each of 2 color difference channels. DV is 411 for NTSC and 420 for PAL. Full resolution broadcast is 422. The 444 is for production work or motion picture conversion.