Canon HF G30 Question on Specs

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    • #56333
      Avatarpseudosafari
      Member

       

      I'm looking at (and drooling over) the upcoming Canon HF G30.  It shoots 24, 30 and 60 fps. When I look at the specs, though, it states the following on the B&H website:
       
      High Definition
      AVCHD
      1920 x 1080p / 60 fps (28Mbps)
      1920 x 1080i / 60 fps (24Mbps)
      1920 x 1080p / 30 fps (17Mbps)
      1920 x 1080p / 24 fps (5Mbps)
       
      What does the Mbps mean?  (I understand it's megabytes per second, but what exactly does it refer to?)  Should I be worried that it's only 5 for the 24fps?
    • #206962
      Avatarbrunerww
      Member

      It's worse than you think.  5 Mbps is 5 megabits per second, not megabytes (1 megabyte = 8 megabits).  That is a pretty low bitrate – but hardly anyone shoots at 24p any more, so it doesn't matter much.  Most people shoot at 1080/60p and conform down to 24p when needed.

       

      If you want high bitrates, you should look at the Panasonic GH3 (specs here).  This camera shoots 24p AVCHD at 24mbps, 60p AVCHD at 28mbps, and 24p & 60p MOV at 50mbps IPB (and that's not even the highest bitrate).

       

      Canon makes great cameras, but they are usually a step behind in the compression game. It must really gall them to pay the licensing fee for the use of AVCHD to the consortium founded by the codec's inventors, Sony and Panasonic πŸ™‚ 

       

      Cheers,

       

      Bill

      Hybrid Camera Revolution

    • #206966
      Avatarpseudosafari
      Member

      Thanks Bill. Sorry to hear that! Sounds bad, but what exactly does the MBS refer to? Is it like bit depth, a reference to the quality of the recording? Or the speed it records to the card at? Or something else?

      also, I note it records in mp4 format, too. I have gotten to like editing AVCHD. Any reason I should switch to mp4 or should I keep avoiding it?

    • #206975
      Avatarbrunerww
      Member

      The best explanation on this that I have seen is from the great Andy Shipsides at Abel Cine. Here are the key paragraphs:

       

       

      "Bit Rate:

       

      Sometimes also referred to as Data Rate, this is a term used to describe the amount of digital information (bits) that is conveyed or recorded per unit of time. In our world, this is typically expressed as an amount of bits per second (bit/s) that make up the digital video signal or recording. The higher the bit rate, the greater the amount of information being transmitted, and generally speaking the higher quality the video signal. When talking about a compressed video format such as DVCPRO HD or XDCAM, the bit rate refers to the amount of data recorded in a second. As the bit rate of a given compression increases, so does the amount of data recorded in a second.

      For example: the XDCAM EX format in its highest quality mode has a data rate of 35 Mbit/s (35 Million bits per second), which translates to about 50 minutes of footage per 16 GB SxS card.

       

      Bit Depth:

       

      Though the word ‘bit’ is also used in this term, Bit Depth actually describes something completely different. Bit Depth, aka Color Depth, describes the amount of information stored in each pixel of data. As you increase bit depth, you also increase the number of colors that can be represented. In the case of an 8-bit RGB image, each pixel has 8-bits of data per color (RGB), so for each color channel the pixel has 28 = 256  possible variations. In the case of a 10-bit RGB image, each color channel would have 210 = 1024 variations."

       

      I bolded the sentence on bit rate to show its impact on image quality.  It is much more important than color depth.

       

      As far as MP4 goes – it is a great format for distrubution, but not that great for production.  I would stick with AVCHD.

       

      Cheers,

       

      Bill

      Hybrid Camera Revolution

       

    • #207003
      Avatarpseudosafari
      Member

      Bill, you read my mind on my next question. Mp4 vs AVCHD. So far I have been pretty happy with AVC HD. I see no reason to change, especially given your notes here. Thanks again.

    • #207760
      AvatarFastfwd
      Participant

      I’m going to guess that is a misprint.  Can anyone confirm that is accurate?  True 24p is a sort of big deal still as far as I am aware. I can’t begin to imagine this camcorder only does 5mbs 24p (sorry if my abbreviation is incorrect).  My HF S20 from only a couple years ago was a big deal for having ‘true’ 24p and it records it at 24mbs. 

       

      If I were to venture a guess; this is something to do with WiFi maybe? A lower bitrate suited for that purpose?  IDK 

    • #301565
      AvatarFastfwd
      Participant

      I’m going to guess that is a misprint.  Can anyone confirm that is accurate?  True 24p is a sort of big deal still as far as I am aware. I can’t begin to imagine this camcorder only does 5mbs 24p (sorry if my abbreviation is incorrect).  My HF S20 from only a couple years ago was a big deal for having ‘true’ 24p and it records it at 24mbs. 

       

      If I were to venture a guess; this is something to do with WiFi maybe? A lower bitrate suited for that purpose?  IDK 

    • #214100
      Avatarmlitty
      Member

      @Fastfwd I have the G30. 23.98 FPS is available at a wide variety of bitrates in both AVCHD and MP4. For example, at 24Mbps AVCHD, it’s possible to shoot at 59.94i, PF29.97 (29.97p in a 59.94i wrapper), or 23.98P. Shooting MP4, at 24Mbps, 29.97P and 23.98P are available. It can also do MP4 at 59.94fps and 35Mbps.

      Lower bitrates are available at various frame rates. Canon definitely has not done away with 24p. It’s fully supported at high bitrates.

    • #72003337
      Avatarkaloyan44
      Participant

      Two years after the purchase of this Canon Legria HF G30 camcorder, I found that all plans were affected by variations in exposure making them difficult to exploit. I suspected a diaphragm problem. Diagnostics confirmed by an authorized Canon workshop; the diaphragm stops. Since the failure occurred gradually and I only use it once or twice a year, I did not really detect it until the warranty expired.
      Canon’s answer to my complaint: we are … sorry not to be able to consider the defect as a “hidden vice”.
      Balance: 20 days of correct operation (excellent quality) and 509 € of repair.

    • #72003640
      CharlesBennettCharlesBennett
      Participant

      They do list the frame and bitrates. In the specifications list scroll down to the Recording Mode section.

    • #207767
      Mike WilhelmMike Wilhelm
      Keymaster

      Canon doesn't mention the bitrate for the different frame rates on their site, but B&H tech specs mirror the OP's numbers. It does seem very low though.

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