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  1. Member
    Join Date: Aug 2007
    Location: South Africa
    Search Comp PM
    Hi All,

    The Vigria/Legria HF G30 is my first foray into the world of HD camcorders and I would really appreciate some help. I'll mostly be shooting holiday videos and the odd wedding video for friends and family.

    My intention is to archive footage in the original format (hopefully high-quality), and also to write some SD DVDs at times. My existing tools will do the job so no problems with that.

    Where I am uncertain is which format to shoot in for best archival quality. The highest AVCHD and MP4 bitrates supported by the G30 are 28 and 35 Mbps resp., both 50p on the Legria. However, there seem to be some differences in encoding format.

    MediaInfo reports 28 Mbps AVCHD as follows:
    Video
    ID : 4113 (0x1011)
    Menu ID : 1 (0x1)
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : High@L4.2
    Format settings, CABAC : Yes
    Format settings, ReFrames : 2 frames
    Format settings, GOP : M=3, N=24
    Codec ID : 27
    Duration : 18s 680ms
    Bit rate mode : Variable
    Bit rate : 26.3 Mbps
    Maximum bit rate : 26.7 Mbps
    Width : 1 920 pixels
    Height : 1 080 pixels
    Display aspect ratio : 16:9
    Frame rate : 50.000 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.253
    Stream size : 58.5 MiB (95%)
    35 Mbps MP4 is reported as follows:
    Video
    ID : 1
    Format : AVC
    Format/Info : Advanced Video Codec
    Format profile : High@L4.2
    Format settings, CABAC : Yes
    Format settings, ReFrames : 2 frames
    Format settings, GOP : M=3, N=24
    Codec ID : avc1
    Codec ID/Info : Advanced Video Coding
    Duration : 12s 960ms
    Bit rate : 34.5 Mbps
    Width : 1 920 pixels
    Height : 1 080 pixels
    Display aspect ratio : 16:9
    Frame rate mode : Constant
    Frame rate : 50.000 fps
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Progressive
    Bits/(Pixel*Frame) : 0.333
    Stream size : 53.3 MiB (99%)
    Language : English
    Encoded date : UTC 2013-12-12 19:45:56
    Tagged date : UTC 2013-12-12 19:45:56
    Color primaries : BT.709
    Transfer characteristics : BT.709
    Matrix coefficients : BT.709
    Although the same profiles and format settings are used, different Codec IDs are reported, AVCHD seems to use VBR and MP4 CBR, and MP4 has a higher Bits/(Pixel*Frame) value.

    I don't quite know what to make of this and lack the knowledge and tools to do an objective comparison. Which format do you recommend?

    Many thanks,
    Francois
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  2. Member
    Join Date: Jun 2012
    Location: USA
    Search Comp PM
    You do have the tools to do an objective comparison: your eyes.

    Shoot some test footage with both settings.

    Test 1: shoot something static with lots of little details.
    Test 2: literally swing the camera back and forth to generate lots of motion

    Watch the footage frame by frame to see which produces the most artifacts -- blocking, rainbowing, over-smoothing.
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  3. Member
    Join Date: Aug 2007
    Location: South Africa
    Search Comp PM
    That helped, thanks. The 35 Mbps MP4 setting is marginally but noticeably better with both. Slightly sharper with static scenes and a little less blocking and banding with lots of motion.
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  4. Member
    Join Date: Sep 2004
    Location: australia
    Search Comp PM
    hi, i am just curious why Canon chose to have 2 video modes using 2 different containers and 2 different bitrates in this camera, given its a consumer grade camera.

    the MP4 container is 35Mbps and the AVCHD wrap is 26Mbps, and in my experience, there seems to be very little quality gain by shooting in the mp4 container at 35Mbps.

    canon shot themselves in the foot with this camera by offering these 2 modes because it bumped the price of the camera up above other similar spec cams that only shoot in AVCHD @ 28Mbps, and personally i would rather shoot at 28Mbps and pay a bit less for the camera, and to me anything over 28Mbps (26Mbps in reality) is of no real benefit and just creates larger file sizes.

    each to their own i guess.
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  5. Member racer-x's Avatar
    Join Date: Mar 2003
    Location: 3rd Rock from the Sun
    Search Comp PM
    They probably included the mp4 choice to make the Apple people happy. I'm sure it's easier for them to import and work with the mp4 than the MTS...........
    Never argue with meaningless people over meaningless topics..............
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  6. Member
    Join Date: Sep 2004
    Location: australia
    Search Comp PM
    interesting that it is still h264 but wrapped in different containers, but i understand for playback support, more devices support mp4 than they do mts/m2ts/ts

    even i have to convert my m2ts files from my cameras to mp4 for many clients so they can play them via their HD tv or hdd media players because they dont support mts or m2ts files.

    some HD tv's wont even play 1080/50p or 60p video regardless of the container, but many will play 720/50p or 60p just fine.
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