Passes, bitrate, Avidemux for MPEG-2 encode?

[Amanjm]

I have captured about 90 VHS tapes using huffyuv in avi container and I am looking for advice to to encode these for watching from a hard drive. There is a large amount of info throughout all the threads and I have read many including the guides, but I have a few questions.

Some details on what I plan to do:

• encode to MPEG-2 since I will largely be watching on watching on TV or computer
• have both Vegas Movie Studio 17 and avidemux - I am comparing outputs from each

Questions:
1. How to best set bitrate and one pass vs two pass for mpeg-2 for good quality?

• I read a recommendation from lordsmurf to use 15mbps for quality.
• The guide shows an example of using constant quantiser.
• How do I set up two pass with 15mbps? Choose "Two Pass" with average bit rate and let it vary?
• Or choose "Two Pass" file size? If so, anyone have some rules of thumb for file size?

2. How to find older version of avidemux? 2.5 specifically.

• Their site has avidemux 2.7 available and I installed that version. It worked in my test for mpeg-2 but have read in several places that I should avoid that version for MPEG-2.
• Any recommendation's on a trusted source for version 2.5?

3. In checking the test file with MediaInfo after encoding using avidemux to mpeg-2 with contstant quantiser, I see the video is showing as interlaced but chroma sampling is 4:2:0. Will this always drop to 4:2:0 when going to mpeg-2?

Here is the readout of my test in MediaInfo:

Video 
ID : 224 (0xE0) 
Format : MPEG Video 
Format version : Version 2 
Format profile : Main@Main 
Format settings : BVOP 
Format settings, BVOP : Yes 
Format settings, Matrix : Default 
Format settings, GOP : Variable 
Format settings, picture structure : Frame 
Duration : 1 min 3 s 
Bit rate mode : Variable 
Bit rate : 7 861 kb/s 
Maximum bit rate : 12.0 Mb/s 
Width : 720 pixels 
Height : 480 pixels 
Display aspect ratio : 4:3 
Frame rate : 29.970 (30000/1001) FPS 
Standard : NTSC 
Color space : YUV 
Chroma subsampling : 4:2:0 
Bit depth : 8 bits 
Scan type : Interlaced 
Scan order : Top Field First 
Compression mode : Lossy 
Bits/(Pixel*Frame) : 0.759 
Time code of first frame : 00:00:00:00 
Time code source : Group of pictures header 
GOP, Open/Closed : Open 
GOP, Open/Closed of first frame : Closed 
Stream size : 59.7 MiB (93%) 

Audio 
ID : 189 (0xBD)-128 (0x80) 
Format : AC-3 
Format/Info : Audio Coding 3 
Commercial name : Dolby Digital 
Muxing mode : DVD-Video 
Duration : 1 min 3 s 
Bit rate mode : Constant 
Bit rate : 384 kb/s 
Channel(s) : 2 channels 
Channel layout : L R 
Sampling rate : 48.0 kHz 
Frame rate : 31.250 FPS (1536 SPF) 
Bit depth : 16 bits 
Compression mode : Lossy 
Stream size : 2.92 MiB (5%) 
Service kind : Complete Main

Thanks.

[lordsmurf]

15mbps ideal, correct.

4:2:2 also suggested, not 4:2:0, using @422 profile. However, not available in Avidemux, only higher-end tools like MainConcept TotalCode.

(ffmpeg can probably do 4:2:2, via command line, but I'm not aware of any GUI that includes the function. Too many GUI encoders are ridiculous in terms of "10-bit vs 8-bit" encoding, but the 4:2:0 vs. 4:2:2 chroma retention will far surpass the quality gains from bit depth alone. It's so shortsighted, and you can often tell which devs actually understand video, and which ones do not.)

There's really no good reasons to 2-pass 15mbps, because the specs of BD/broadcast call for CQ/CBR (but also 4:2:0). If you want to do a true VBR, you can, but it's somewhat pointless. At that bit depth, the GOP makes a bigger savings than bitrate if trying to conserve space. I'd do no more than 10min, 25 max, 15avg, if VBR. And 2-pass if VBR. Standard GOP or less (more frequent I and P).

The official site has 2.5.6 download: https://sourceforge.net/projects/avi...videmux/2.5.6/

PAL or NTSC?

[Amanjm]

Quote:

Originally Posted by lordsmurf

PAL or NTSC?

NTSC

Quote:

Originally Posted by lordsmurf

4:2:2 also suggested, not 4:2:0, using @422 profile. However, not available in Avidemux, only higher-end tools like MainConcept TotalCode.

Thanks. Looking at the price of TotalCode I will stick with the free programs.

If I was willing to deinterlace, would the quality drop off be a lot of I went to a quality h.264 encode in mp4? I tried mp4 in Vegas Movie Studio and the output lost a lot of sharpness was lost. However, I can use TotalCode free version for h.264. Issue there is I get subtle lines across the image. Maybe I could also use avidemux.

Quote:

Originally Posted by lordsmurf

There's really no good reasons to 2-pass 15mbps, because the specs of BD/broadcast call for CQ/CBR (but also 4:2:0). If you want to do a true VBR, you can, but it's somewhat pointless. At that bit depth, the GOP makes a bigger savings than bitrate if trying to conserve space. I'd do no more than 10min, 25 max, 15avg, if VBR. And 2-pass if VBR. Standard GOP or less (more frequent I and P).

I looked up the acronyms and think I follow. With a goal of having good quality files, better than DVD, that can be viewed on a HTPC from hard drive, I was thinking broadcast MPEG-2 or H.264.
If using MPEG-2, are you suggesting one pass CQ? If so, is there a Quantiser setting recommended?

Also, are you recommending I only encode up to 15 min at once?

[lordsmurf]

Deinterlace often required for h264 playback in LAN stream boxes, for sure online streams. Quality loss is mostly about method (use QTGMC), sometimes framerates, not really chroma.

MPEG-2 for HTPC/LAN, yes, you got it.

15mbit = 15000k bitrate
15avg = average bitrate in VBR (min/avg/max settings)

[Amanjm]

Quote:

Originally Posted by lordsmurf

15mbps ideal, correct.

4:2:2 also suggested, not 4:2:0, using @422 profile. However, not available in Avidemux, only higher-end tools like MainConcept TotalCode.
...
PAL or NTSC?

NTSC.

An update - I walked away from this for a while because it was just hard for me to spend the time needed to learn all the facets of the process given other things going on in my life at the time. I am back and looking to get these files converted.

Question 1: Can I use Adobe Media Converter to get 4:2:2 and will it do a good job? I have not found any guides on using this software to accomplish this but I have read that it uses MainConcept TotalCode process (this is not the right terminology but I am having a hard time finding the right words) to encode.

Question 2: I may need to encode some videos as h.264 - would AME work well for this? Would it also deinterlace well or only encode? The name likely gives it away as an encoder but looking to simplify if I can as I have not figured out how to deinterlace using QTGMC.