What is difference between 1 pass encoding & 2 pass encoding

[Computerman1]

If I convert Blu-ray film to MKV h.264 format and I set the size 16000 MB ? (additional information about what settings I use attached).

Whether in this case the best One pass or Two pass? The file size I choose for yourself , and it is less than 18000 mb. I want the best quality, the size of 16000 mb

I watch movies in Full HD screen. I use Freemake Video converter program.

[KarMa]

1 Pass = Faster but worse quality and bitrate inefficient
2 Pass = Better Quality for the file size

Considering you seem to be new to video conversion, I would suggest Handbrake, Vidcoder, or any program that uses x264 and gives you control over its settings. Instead of Freemake Video converter which is not designed for quality.

[Computerman1]

Yeah but Freemake is very easy to use.

So, this two pass is the best way if you want the best quality for file size ?

[KarMa]

Yeah but Freemake is very easy to use.

Handbrake is also pretty easy, just use the simple x264 presets options. There are better quality options out there than freemake.

So, this two pass is the best way if you want the best quality for file size ?

Inside freemake yes.

[LigH.de]

Thumb rule: If you want to fill a given capacity with optimal quality, you need 2-pass encoding. Every movie has a different ratio between quality conservation and required bitrate. The statistics from the 1st pass are necessary to calculate the optimum for the 2nd pass.

BTW, isn't Freemake one of those "spyware injecting installations"?

[Computerman1]

Thumb rule: If you want to fill a given capacity with optimal quality, you need 2-pass encoding. Every movie has a different ratio between quality conservation and required bitrate. The statistics from the 1st pass are necessary to calculate the optimum for the 2nd pass.

BTW, isn't Freemake one of those "spyware injecting installations"?

Yeah i want best quality= the specific size (for example 16 GB). If you install Freemake, you can remove any spyware program the installation stage

[KarMa]

Freemake also puts a watermark at the end of the video, for those that don't donate Even though all they use is the free ffmpeg for most of the encoding.

[jagabo]

x264 2 pass: You specify the file size (indirectly by setting the bitrate) but you don't know what the quality will be.

x264 1 pass CRF: You specify the quality (the lower the CRF the higher the quality) but you don't know how big the file will be.

When the two methods deliver the same file size (other settings being equal) the quality is about equal.

Use 2-pass when you need a file of a specific size -- like when putting a movie on a 4.3 GB DVD. Use CRF encoding when you want to be guaranteed a specific quality.

[KarMa]

x264 1 pass CRF: You specify the quality (the lower the CRF the higher the quality) but you don't know how big the file will be.

I was going by the assumption that Freemake did not support CRF, or OP only wants to use ABR 1-Pass/2-Pass

[Computerman1]

I use after all 1 pass because 2 pass take about 10 hour per HD mkv file! I just tested..

And I set myself the size , or do not allow the program to determine. I think that the quality remains good.

[LigH.de]

1-pass encoding with an average bitrate (to achieve a given target size) is about the worst quality mode. It is only useful for cases where the bitrate should not vary a lot; but then the quality during the movie will vary a lot.

To encode compatible to optical media (like DVD-R or BD-R{E}), you may use a variable bitrate to achieve a rather constant quality; but it needs to be restricted to the reading speed and the size of the decoding buffer. You must be able to add VBV parameters to the encoder's command line. If your converter doesn't offer such parameters, it is not able to certainly create compatible video streams, and you will risk playback stopping in certain scenes.

[KarMa]

I downloaded/installed Freemake (was sure to avoid the adware). Tried to encode two videos at 100kbps into an MKV but it refused to do so and so gave me 1072 for both encodings. It does infact use x264, with seriously fast/bad settings for the One Pass. Two pass uses a bit better settings but could still go a lot further.

One Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x131 / me=dia / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00

Two Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.41 / aq=1:1.00

[Computerman1]

I downloaded/installed Freemake (was sure to avoid the adware). Tried to encode two videos at 100kbps into an MKV but it refused to do so and so gave me 1072 for both encodings. It does infact use x264, with seriously fast/bad settings for the One Pass. Two pass uses a bit better settings but could still go a lot further.

One Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x131 / me=dia / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00

Two Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.41 / aq=1:1.00

Ok. I do it Two pass even if it takes days .

[jagabo]

I downloaded/installed Freemake (was sure to avoid the adware). Tried to encode two videos at 100kbps into an MKV but it refused to do so and so gave me 1072 for both encodings. It does infact use x264, with seriously fast/bad settings for the One Pass. Two pass uses a bit better settings but could still go a lot further.

One Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x131 / me=dia / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00

Two Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.41 / aq=1:1.00

You were right, it does use ABR in single pass mode. And settings very close to the veryfast preset. I thought no program would be stupid enough to use ABR! 2 pass mode is a lot better, close to the fast preset.

[Computerman1]

I downloaded/installed Freemake (was sure to avoid the adware). Tried to encode two videos at 100kbps into an MKV but it refused to do so and so gave me 1072 for both encodings. It does infact use x264, with seriously fast/bad settings for the One Pass. Two pass uses a bit better settings but could still go a lot further.

One Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x131 / me=dia / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=abr / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.41 / aq=1:1.00

Two Pass
Writing library : x264 core 129
Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=6 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=6 / lookahead_threads=1 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=2pass / mbtree=1 / bitrate=1072 / ratetol=1.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / cplxblur=20.0 / qblur=0.5 / ip_ratio=1.41 / aq=1:1.00

You were right, it does use ABR in single pass mode. And settings very close to the veryfast preset. I thought no program would be stupid enough to use ABR! 2 pass mode is a lot better, close to the fast preset.

Ok. I use two pass mode! Thank you for all the help.

[Lathe]

Okay, this kind of related... and rather specific. This would probably be the ONLY case where I am tempted to use ABR (even with Jag's rather sobering comment above ) I pretty much use BDRB exclusively. Normally if the Blu-ray is any real size at all, I usually set everything pretty high, 2-pass, x264 Tweaks, etc. But, when I have a Remux, or movie only file that is about, say, 26 Gigs, it only needs to be compressed by a few Gigs. So, like right now, when normally I almost always would do a 2-pass moderate settings, milder x264 Tweaks, I thought maybe I'd try the 1-pass ABR setting with mild x264 Tweaks. But, after reading the comments here, I'm starting to think that maybe I shoulda gone the 2-pass route.

The only justification I was thinking about is that only about 3 Gigs needs to be taken out.

Any thoughts on THIS kind of particular case when you are working with pretty high bitrates (in excess of 27,000 I think in this case, and some Tweaks that will HOPEFULLY bump up the quality a tad:

TWEAK_PASS_TWO=--deblock -1:-1 --psy-rd 1.00:0.25 --me hex --subme 6 --trellis 1

Appreciate the experienced input guys!

Cheers!

[Lathe]

Oh, the other thing that made me try this, is that this isn't a real technical, Sci Fi film or anything like that. It is a Horror film, but not with like state of the art pyrotechnics or what I would think are high demand visuals...

[jagabo]

You're right that the quality difference between 2-pass VBR and 1-pass ABR is small when working at high bitrates. On the other hand, since the first pass is typically much faster than the second pass, the difference in overall encoding time isn't that large, with two-pass taking about 25 percent longer. The additional quality of the 2-pass encoding will pay off every time you watch the movie.

[Lathe]

You're right that the quality difference between 2-pass VBR and 1-pass ABR is small when working at high bitrates. On the other hand, since the first pass is typically much faster than the second pass, the difference in overall encoding time isn't that large, with two-pass taking about 25 percent longer. The additional quality of the 2-pass encoding will pay off every time you watch the movie.

Yeah, I kinda thought so...

Thanks kindly for the fast answer Jag!

Cheers!