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  1. -I have a couple big L4.1 MKV videos & i want to shrink them down to web optimized MP4
    -input files are HIGH L4.1 MKV with DTS or AC3 audio
    -desired output is HIGH L3.1 MP4 with AAC audio, "WEB OPTIMIZED" option & CRF (Constant Rate Factor) encoding

    -I tried XVID4PSP before, but the audio turns into static & seems there's no WEB OPTIMIZED option
    -The VIDCODER rip has no audio problems, but always ends up with VFR (Variable Frame Rate), even when i set the FPS manually?
    -both of these apps work fine when i reencode the same settings to output an MKV. So i could reencode to MKV, then remux to MP4 with REBOX, but seems rebox has no WEB OPTIMIZED option
    -I guess VIDCODER is the only one with the WEB OPTIMIZED option?

    -Are there any specs to making sure an MP4 is WEB OPTIMIZED?
    -what is the difference between AAC HE or AAC LC regarding compatibility for apple tv 2/xbox360/wdtv live/etc?
    -what is the difference between CONSTANT QUALITY and CONSTANT QUANTIZER? do they both use CRF (Constant Rate Factor)
    Last edited by J81CHAT; 27th Feb 2012 at 02:20.
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  2. Let's pretend those mkv's are yours.

    Web optimazed for video is never the same and easy like web optimized for jpg , golden rule in Photoshop Shift+Ctrl+Alt+S , jpg, 50% , done . In video realm it is always relative because those damn stills move and there is limit what can CPU handle.

    CRF - your bit rate will not be constant or close to some number. It will go up or down depends on your video. 2pass comes handy here with average bitrate settings.

    NOt sure if it would make any sense to set maximum and minimum, because the enemy is weak CPU inside older computers, not bandwith and with this low rate already (my opinion) Pentium 4 handles so, so this one for example : mpeg4 avc, 1000kbps, Base@level 3 (basicaly using Ipod 5.5 setting within MeGui) . Then you have to choose resolution. Only you will know what is going to be good for you . 720x406... who knows 512x288 with real messy video ..? Lower resolution helps not to choke CPU again ... 1000kbps will fluctuate from 600kbps to 2500 max, only peaks occasionally , mostly max will be around 1500, always depends on video ...

    for WDTV AAC-HE or AAC-LC makes no difference
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  3. Originally Posted by _Al_ View Post
    Let's pretend those mkv's are yours.

    Web optimazed for video is never the same and easy like web optimized for jpg , golden rule in Photoshop Shift+Ctrl+Alt+S , jpg, 50% , done . In video realm it is always relative because those damn stills move and there is limit what can CPU handle.

    CRF - your bit rate will not be constant or close to some number. It will go up or down depends on your video. 2pass comes handy here with average bitrate settings.

    NOt sure if it would make any sense to set maximum and minimum, because the enemy is weak CPU inside older computers, not bandwith and with this low rate already (my opinion) Pentium 4 handles so, so this one for example : mpeg4 avc, 1000kbps, Base@level 3 (basicaly using Ipod 5.5 setting within MeGui) . Then you have to choose resolution. Only you will know what is going to be good for you . 720x406... who knows 512x288 with real messy video ..? Lower resolution helps not to choke CPU again ... 1000kbps will fluctuate from 600kbps to 2500 max, only peaks occasionally , mostly max will be around 1500, always depends on video ...

    for WDTV AAC-HE or AAC-LC makes no difference
    -what bitrate do u suggest for 720p? seems APPLE TV 2 is the least compatible, so i guess my rips will be limited to whatever that'll play.
    -i think i used to use megui for xvid, thanks, i'll try it out. i used to use size encoding, then switched to avg bitrate, which is effective, but i just want to try CRF too
    -is AAC HE is better than LC? if so, what bitrate AAC HE is equal to 128kbps mp3
    -did some more research, only constant quality uses CRF & seems its better than constant quantizer
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  4. MkvToMp4 author oreons's Avatar
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    Try MkvToMp4, it's for the Apple devices.
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  5. Originally Posted by J81CHAT View Post
    -did some more research, only constant quality uses CRF & seems its better than constant quantizer
    Constant quantizer (CQ) is constant quality in a mathematical sense. Say you have a list of 4 digit integers. You can compress the list to half the size (2 digit integers) by dividing them all by 100. Then restore the original list (decompress) by multiplying by 100. Of course, the numbers won't be exactly the same because of rounding errors.

    CRF (constant rate factor) is constant quality in a more visual sense. It takes into account what the human eye can see. Because of this it can deliver better visual quality at the same bitrate, or lower bitrate with the same quality as CQ encoding.

    CQ and CRF encoding are not good for web streaming because they can result in very high bitrate peaks in some scenes.
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  6. Originally Posted by oreons View Post
    Try MkvToMp4, it's for the Apple devices.
    i didn't know i could add artwork, thanks, i'll check it out

    Originally Posted by jagabo View Post
    Originally Posted by J81CHAT View Post
    -did some more research, only constant quality uses CRF & seems its better than constant quantizer
    Constant quantizer (CQ) is constant quality in a mathematical sense. Say you have a list of 4 digit integers. You can compress the list to half the size (2 digit integers) by dividing them all by 100. Then restore the original list (decompress) by multiplying by 100. Of course, the numbers won't be exactly the same because of rounding errors.

    CRF (constant rate factor) is constant quality in a more visual sense. It takes into account what the human eye can see. Because of this it can deliver better visual quality at the same bitrate, or lower bitrate with the same quality as CQ encoding.

    CQ and CRF encoding are not good for web streaming because they can result in very high bitrate peaks in some scenes.
    oh i see, makes more sense now. I guess i'll go back to bitrate encoding while i test out CRF later.

    learned more about AAC HE & LC, i guess HE 64k & LC 96k are close to a 128k MP3. I'm unsure about the XBOX360, but seems apple itunes uses ABR for aac audio, so i guess i'll use ABR instead of CBR.
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