I need help deciding on a good video bitrate, I am encoding from a DVD to a 480x272 resolution, I have converted at 1024, is that good enough? I do want very high quality.
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Once again, another poster thinks we are mind readers. OK, how are you encoding to 480x272? Using Divx or Xvid? H.264/X.264? Something else?
If you are encoding to H.264/X.264, then a bit rate of 1024 should be fine. If you are encoding to Divx/Xvid, then it probably will be OK at that bitrate. If you are using something else, then that bitrate probably won't be enough. -
Unless you have specific hardware or file size requirements forget bitrate. Use constant quality or constant quantizer encoding. Select the quality you want and encode in a single pass. The resulting video will have the quality you specify. The file size (bitrate) will be whatever it takes to deliver that quality.
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I don't care about file size, just wondering whether 1024 would be good for a video 480x272 resolution for any codec. Thank you
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Originally Posted by Nitro89
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That's too subjective of a question to answer. It might be ok for some people, might look like crap in other people's eyes.
If you want a set bitrate, the source material is important to consider: A still movie of a plant leaf with 1 color will not need a very high bitrate. An action packed movie with complex sequences & movement will require a higher bitrate to look decent
Encode some small representative clips at various bitrates, and test it yourself if YOU think the quality is acceptable. -
You will not fit the same clothing size on everybody, and even so, every body will have different tastes such as a tighter, looser, shorter, etc. fit. It is very subjective as Poison mentioned.
That's how fitting one "good bitrate" on every video is like. You can have the bloated MPEG-2 make a clip of all black screen look great at 200kbps, but you can have the efficient x264 codec look terrible at 1024kbps with a movie of lots of movement, action, flashes, etc. But even if you may find it terrible, the next guy may love it (as Jman98 pointed out). So no one can answer your question.
And I agree with Jagabo - use quality based encoding, especially when you don't care about file size. Pick a quality level, and the encoder will give you the smallest possible file size for the resolution and fps that you use. Let it do the thinking for you to determine what's necessary for a quality that YOU like.
Honestly, my days of trying to find the right bitrate are long over - I have been much happier letting encoders with quantizers and quality based encoding do it for me.I hate VHS. I always did. -
The best thing is to experiment with various bitrates and resolutions (D1 versus half D1 for example) and make the judgment for yourself based on your own perception of video quality versus file size etc. Unfortunately this whole subject is very subjective and it is very often used for "ego spin" purposes by various people. Basically if you don't do it their way, they are apt to be critical as a way to assert their own superiority (as if you or anyone else cares). Your own judgment based on your own perception is the most important consideration. Things like viewing distance, screen size, screen resolution affect the perception of what is acceptable. Only you can make that determination, certainly not some joker who is trying to use a back-door put-down as a way to assert his own "superiority". This thread has been very civil and helpful but if you look through many of the threads on this forum, you will see what I mean about the self aggrandizing clowns who like to use resolution as a platform to show their own brilliance versus the deficiency of others.
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Here's a 720x480 xvid encoding at only 1 kbps:
xvid.avi
It's boring but it looks just fine, doesn't it?
Here's another video encoded at the same quality setting (target quantizer = 3) in Xvid:
static.avi
It's boring too but the bitrate turned out a little higher, 67,000 kbps. -
@SCVCD: I see you're well versed on these details from your posts regarding the psychology of the members. Alot has to do with the Maslov hierarchy of needs. But not only is this a general theory, it even applies on a micro level - even within sub-needs like why we do video, or video forums, in the first place.
Most overlook the fact that alot of argument here is really based on the fact that everybody has different priorities in this hobby: file size, quality, compatibility, specific playback device, best encoding speeds, ego, amusement, career contacts, etc., so there's bound to be friction even if everybody may make a good point.
I prefer making contacts, but my top 3 personal video needs are 1)widest compatibility 2)best quality 3)smallest file size, etc.
If someone is centered on small file sizes and another on quality-at-any-cost, or fastest encoder, or anything else, then there's bound to be disagreement among all of us.
This variance can be nice, but alot of arguments stem from it as well. Indeed, alot of what's said here is highly subjective.I hate VHS. I always did. -
Jagabo just proved an earlier point - every video is unique in its needs and length has less to do with it than may seem.
I personally encode tons of music videos with codecs like DivX and H.264. If you want variance, you couldn't have found a better collection of small clips.
Here's another example. These aren't my uploads, but you will get an idea how my sources worked out. Using DivX, at the same quantizer (Q=4) for both:
Bitrate of under 700kbps for this one. (You can tell the Pixies were very sarcastic - that *is* the actual music video!)
Bitrate of over 4000kbps for this one. (Ok, this one is cheesy, but since I'm a collector, I had to appreciate its historic value. Too bad it takes more space...)
And both videos resulted in the same quality. You can see the higher bitrate requirements of the latter with all that motion, lights, etc. No wonder there was such a disparity in bitrate.
I even got a similar gap using x264 as well.I hate VHS. I always did. -
Originally Posted by PuzZLeR
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I don't do a lot of h264 encoding but when I do I use x264. I find that a quantizer of 18 is about the equivalent (in terms of image quality) of Xvid at 2 -- near lossless. x264 at 22 is about equal to Xvid at 3.
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hello again, I am now encoding cartoons, I am still using MPEG4 AVC/h264 compressions, however "18" is a way too big quantizer for this task and I am also using Average Quantizer. For a cartoon like the Simpsons, what's a good quantizer size?
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Originally Posted by Nitro89
You want a larger quantizer, not smaller quantizer for a smaller filesize. Try --crf 22. If you want an exact filesize you have to use 2passes avg. bitrate
For simple cartoons (not CGI type), consider turning off psy options (i.e. --psy-rd 0:0), or at least lowering from the default values; increasing deblock alpha and beta (i.e. --deblock 1:1) , and maybe even disabling AQ (ie. --aq-mode 0) -
I thought average bitrate is better then constant, because your not wasting more bitrate resulting in a bigger file size?
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CRF is not constant bitrate. It's constant quality in a visual sense. CQP is constant quality in a more mathematical sense.
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Keep in mind that CRF=24 is not a standard of any sort for good quality and file size - in fact, there isn't one. The "standard" is what you yourself are happy with.
Some of us are willing to pay more bitrate for something like CRF=21, and some of us are happy with the quality at CRF=26 for tiny file sizes. It's totally subjective. But I'm glad you found your sweet spot.
Also keep in mind, that if you do indeed like CRF=24, you can expect similar quality for all clips you use it with (hence the name "constant quality"). The bitrate may vary as each clip is unique, but CRF will give you the lowest bitrate possible for the quality level (24 in your case) that you ask of it.I hate VHS. I always did. -
I don't understand what is meant by "Average" Quantizer, won't "Average" be better then "Constant" because it is using lower bitrate for parts where it is needed and more bitrate for parts which need more?
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Constant Quality aka CRF adjusts the bitrate as needed so that every frame gets just enough bitrate to look the same (quality wise) as any other frame. The lower the number the better the quality because a higher bitrate is used. I've found that with H.264 that "18" is a very good number although it can cause a "big" file. Sometimes as a compromise I'll use "19" or "20" instead. I've found that "21" causes too many artifacts unless the source is damn clean or is animation.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Both Constant Quantizer and Constant Rate Factor are variable bitrate modes. Not every frame of video requires the same number of bits to maintain the same quality for that frame. For example, an all black frame can be represented with just a few bits. A highly detailed image requires a lot of bits to describe it well. A frame which is exactly the same as the last one doesn't have to be encoded again, the encoder can just say "repeat the last frame." Constant quality modes tell the encoder to encode each frame with the same quality, regardless of how many bits it takes.
CQP mode is constant quality in a very mathematical sense. CRF mode also takes into account the fact that human vision is less sensitive to some losses than others. -
I've been doing a lot of H.264 encoding via XVID4PSP which uses x264 and often I use "18" constant quality but like I said above sometimes "19" or "20" but I notice that even on the "18" setting that sometimes for a very brief moment there is some artifacts on scenes that fade in or fade out. Otherwise I never really see artifacts from the encoding (knock on wood).
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Originally Posted by FulciLives
I have noticed "ringing" sometimes at lower bitrates or >CRF22 encodes when using default settings. Current x264 builds have --psy-rd set at 1.0:0 by default which can cause ringing in some scenes, worse at low bitrates
You can change deblocking to 0:0 and --psy-rd to 0:0 and chances are the ringing type artifacts will disappear; I've found that it really depends on the source material, but personally I don't think the psy enhancements should be enabled on the default settings
But it sounds like you are describing something else? If this is a repeatable event, maybe post a sample source clip over @ Doom9 - this way the developers can "fix" it if there is a problem -
I'll see what I can do about posting a sample clip but basically I've noticed on fade in and fade out shots that the screen will get sort of "blocky" looking for a moment or two. I'm assuming it's not getting enough bitrate.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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Originally Posted by FulciLives
Transitions, such as fades, break this assumption. Even if you are fading on a still image, every pixel is touched and changed. because of this, each frame needs a much higher amount of data to store the details. If you are encoding with a constant bitrate, or a quality based encode with too low a value, these brief segments may not get enough bitrate to adequately handle the changes.
Studio release DVDs are generally hand tweaked. That is, an operator goes through it scene by scene, change by change, and adjusts the bitrate settings in ranges of frames if necessary to ensure that the required bitrate is given to troublesome areas, such as transitions and major scene changes. Most consumer encoders have rudimentary scene change detection built-in to cater for cuts and hard shifts, but these tend to fail, often badly, when it comes to slower transitions, such as fades.
Finally, with mpeg-4 variants, you also have the additional issue of intra-frame compression that often causes blocking artifacts in areas of low contrast and low tonal difference. As fades get darker, the likelihood of this type of artifact appearing increases.Read my blog here.
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I am perplexed by fulci's observations, because at CRF22, I can honestly say I have never seen blocking using a modern x264 build in the scenario described. For XviD/DivX it's common for this to occur in this scenario, but not for h264 in my experience.
If this is a repeatable event and something is confirmed to be "broken", seriously consider uploading an unprocessed sample over at the AVC subforum, I'm sure they will fix it promptly
There was a big thread over at Doom9 about this exact topic, but it was later revealed that the poster turned off deblocking and used CRF30...
What guns1inger is saying about manually adjusting the bitrate is actually not too difficult to do using zones. It's setup to use quite easily in MeGUI. You might use it by decreasing quants on complex scenes or increasing on simple scenes like credits, for example -
I am at work and even when I get home I don't know if I'll have time tonight but I will post an example. It just might take a day or two or three ...
I know I've seen this more than once but the specific encode I am thinking of is one I just did a couple or so weeks ago. It was a PAL DVD rip. I used XVID4PSP and used the "MP4 PS3 / XBOX 360" setting and used the "Q18 Ultra" setting ... In fact I might have used "Q18 Extreme" ... can't remember for sure but I know it was one or the other.
- John "FulciLives" Coleman"The eyes are the first thing that you have to destroy ... because they have seen too many bad things" - Lucio Fulci
EXPLORE THE FILMS OF LUCIO FULCI - THE MAESTRO OF GORE
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