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1) Does "B-Frame as Reference Frames" feature improve output video quality? (I mean, should I enable or disable it?)

2) In "Sorenson Squeeze" software, there is "Number of B-frames" range (not b-frame bias) of 0 to 100 (in x264 codec), so I can adjust any value of B-frames from 0 to 100. So, please tell me should I adjust the value 100 to result better quality? (Or, which value should be optimal for me? because I realy don't care about encoding speed, I just need HIGHEST QUALITY)

3) Should "pyramid B-frame" feature work, if "Number of B-frames" value is more than 3 ?

4) What is "DPB (Decoded Picture Buffer) size", and which value is the best to adjust? (The value is from 0 to 16)

5) (This is from H.264 codec) Which value should I adjust on "Mark Every * I-frame as IDR" (The value is from 0 to 100'000)


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closed as not a real question by slhck, random May 13 '12 at 18:02

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Use proper tags please, this has nothing to do with Windows. – slhck May 12 '12 at 23:52

Max. Ref. frames: In contrast to MPEG-4 ASP, H.264 allows multiple reference frames. This setting controls how many frames can be referenced by P- and B-Frames. Higher values will usually result in a more efficient compression, which means better visual quality at same file size. Unfortunately more reference frames will require more time for encoding (and also a tiny bit more CPU power for playback). By default the number of reference frames is limited to 1. It's highly recommended to raise the number of references to at least 3. Nevertheless using more than 4 or 5 reference frames for “real life” footage should be avoided, as it won't improve the results any further! At the same time Anime and cartoons benefit a lot from additional reference frames. Sometimes even the maximum of 16 reference frames can be helpful for such material.

Max Consecutive: This setting controls the maximum number of consecutive B-Frames. B-Frames refer to both, the previous and the following I-Frame (or P-Frame). This way B-Frames can compress even more efficient than P-Frames. B-Frames can significantly improve the visual quality of the video at the same file size. Therefore using B-Frames is highly recommended. Also note that allowing more B-Frames will never hurt the quality: You can even safely choose the maximum of 16 consecutive B-Frames. That's because you only specify the upper bound for the number of consecutive B-Frames. x264 will still decide how many consecutive B-Frames are actually used. So even if you allow up to 16 consecutive B-Frames, the encoder will rarely go that high. Nevertheless limiting the maximum number of B-Frames to less than 16 is reasonable, because most videos won't benefit from using more than ~4 consecutive B-Frames anyway! Raising the B-Frame limit higher than that would only slowdown the encoding process for no real benefit! If you set the B-Frame limit to 0 (the default), B-Frames will be disabled. Of course disabling B-Frames is not recommended!

So... depending on how much CPU you want to dedicate to playing back this video, the higher the better... all things considered. I mean 5 should be great, you might even try a little more with 6 or 7 (unless it's a cartoon as noted). Just remember, the load on the CPU during playback with 5 or so should be noticeable.


Default: normal

Allow the use of B-frames as references for other frames. Without this setting, frames can only reference I- or P-frames. Although I/P-frames are more valued as references because of their higher quality, B-frames can also be useful. B-frames designated as references will get a quantizer halfway between P-frames and normal B-frames. You need to use at least two B-frames before B-pyramid will work.

If you're encoding for Blu-ray, use 'none' or 'strict'.

  • none: do not allow B-frames to be used as references.

  • strict: allow one B-frame per minigop to be used as reference; enforces restrictions imposed by the Blu-ray standard.

  • normal: allow numerous B-frames per minigop to be used as references.

Now... Decoded Picture Buffer is a computed value. YOU must compute the value based on specifics in your media. Here...

Previously-encoded pictures are used by H.264/AVC encoders to provide predictions of the values of samples in other pictures. This allows the encoder to make efficient decisions on the best way to encode a given picture. At the decoder, such pictures are stored in a virtual decoded picture buffer (DPB). The maximum capacity of the DPB is in units of frames (or pairs of fields), as shown in parentheses in the right column of the table above, can be computed as follows: Reference page with Formulas to use at Wikipedia

So, as you can see, no one can give you the value you should use for Decoded Picture Buffer, as no one knows the specifics of your media that you are encoding.


IDR frames are a complete refresh of the video frame

So, an increase in IDR will increase CPU usage during playback. How many IDR frames you want is up to you. It's more about maintaining quality than improving quality, as every time you completely refresh the video frame you are increasing the amount of data in the frame. A ton of IDR would necessarily mean a larger video filesize after encoding.

On a side note, I notice you haven't gotten an answer to these questions yet at the Sorenson Media forums. If you paid $800 for this software (because that's what it costs, roughly), why haven't you contacted Sorenson Media directly for an answer to these questions? You paid for the support... they don't offer direct support to people who haven't paid for the software. I also got a majority of this information from where I also see you posted and asked these questions... and you were quite specific about not wanting to have explanations about what these settings meant... you just wanted to be told the numbers to set these things at to get the best possible quality. You were also informed that it really wasn't possible to just give you numbers without explanations, since the numbers you want vary for the media that is to be encoded, and you provided no specifics on the media.

Plus for some people with a powerful processor and with no intention of ever playing their encoded work on another machine, they would choose one set of settings. However, their encoded project would play like total garbage on someone else's machine. You said nothing about your intentions here. But as I pointed out, a couple of guys at mentioned to you that you really need to TRY and UNDERSTAND these settings, so you can find the settings that work best for you.


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Thanks for that last paragraph. I've been coming to the same conclusion with that OP, who hasn't even bothered to respond to answers. – slhck May 12 '12 at 23:44

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