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  1. I performed encoding on a video with a target size of 2.1GB. Once with 1280px width, then again at 720px.

    The video is quite fast paced, so on viewing (HDTV 37"), I couldn't really notice much difference. Anyone care to leave some input on file size to resolution recommendations?

    I'm particularly interested in the following file sizes:
    1.4GB, 2.8GB, 4.2GB.


    I encoded to MKV H2.64 with audio (as original) AC3 5.1 350MB.
    Last edited by pizzaboyUK; 13th Sep 2014 at 08:46.
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  2. Member DB83's Avatar
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    There is no direct correallation between filesize and resolution. The formula is filesize = bitrate(avg) * runlength.

    Resolution can play an indirect part if your bitrate is too low for your content but your encoder settings are also important.

    It would help if you stated what program you use to encode. But if you just use a target size you have no real control over bitrate and, ultimately, quality.
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  3. As I've set a target file size, the bitrate is automatically calculated...

    Doh!! I deleted the files... was going to tell you what the bitrates were for the 1280 and 720


    So 1280px and 720px would result in the same quality based on that assumption?

    I'm sure I read somewhere that for encoding the larger the resolution the better, though they never mentioned restricting the size of the encoding - can't seem to find any info with regards to that...
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    It follows that the bitrate was the same for both the 1280 and 720 files.

    It also follows that the larger the target size, the higher the bitrate would be.

    On a strict target size, the quality is, therefore, the same.

    But we still need to know what software you use. There are a whole lot of settings for h264 which can help with quality especially if you do not need to be too strict with ultimate file size.
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  5. I'm using VidCoder (a GUI for Handbrake). Resolution for the file was 1280px width, I think... 404px height.

    Keep Aspect Ratio... Anamorphic: None. Cropping: None.

    FPS: Same as source (23.976), Constant.

    Audio: Auto Passthrough (original was AC3 5.1, around 350MB)

    2-pass encoding. Not using Turbo first pass.
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    I would use crf settings and keep dropping the quality until you reach that "special" target file size. 720p is 720p, we all know that refers to 1280. The higher the file size, the higher the bitrate (quality).
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    I realise that is what it says 'on the tin' but I would never describe vidcoder as a gui for handbrake which is itself a gui.

    Not familiar with the program so I do not know how advanced its setting are as compared with handbrake.

    The settings you mention tell us nothing. But even handbrake's fixed target settings would probably give similar results as both of these ultimately use the same x264 encoder.
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  8. Originally Posted by DB83 View Post
    But even handbrake's fixed target settings would probably give similar results as both of these ultimately use the same x264 encoder.
    Sorry... still bit of a newbie

    Care to elaborate... and advice would also be great
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    x264 encoder = x264 codec

    It doesn't matter which software you use. They will all use the same plugin (x264)
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    The reason for asking about the software was to direct the replies specific to any peculiarities of that. Yet I now see the OP, in another thread, writing about handbrake so this becomes academical.
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  11. Originally Posted by DB83 View Post
    It follows that the bitrate was the same for both the 1280 and 720 files.

    It also follows that the larger the target size, the higher the bitrate would be.

    On a strict target size, the quality is, therefore, the same.
    This is very interesting, guess I'd never considered that before...

    What bitrate would consider a good tradeoff for 720P, compressed, obviously...
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    Not a question that is readily answerable.

    Fast action requires more bitrate than little or no action.

    Noisy film sources require more bitrate than current HD sources.

    You just have to experiment. It is your own eyes that are the best judge.
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  13. Just find a CRF value you're comfortable with - 18, 20, whatever - and be done with it. You're asking unanswerable questions as there's no correlation between filesize and quality, unless the source is taken into account. One size doesn't fit all.
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