In the previous post, we looked at the scope of the series and the tools that will be required.
In this post, we are going to be covering the most important piece of authoring Blu-rays: specifications. You can mux any video and audio input into a container file, burn any video and audio streams to a disc, encode any source to an output of your choosing and call it "HD" or Blu-ray compliant. That does not make it so. There are specifications that must be followed in order for your content to be deemed Blu-ray compliant. Compliance is important because if the media you author is Blu-ray compliant, you can be sure that it will work on any Blu-ray player.
In order for your media to be considered Blu-ray compliant, the following rules must be followed. We are only going to concern ourselves with the Blu-ray spec at this time, which will exclude Ultra HD Blu-ray and Blu-ray 3D.
MPEG2 - Main Profile at High Level (MP@HL) or Main Profile at Main Level (MP@ML) h264 (AVC) - High Profile at 4.1/4.0 Level (HP@4.1/4.0) or Main Profile at 4.1/4.0/.3.2/3.1/3.0 Level (MP@4.1/4.0/3.2/3.1/3.0) h265 - High Profile at 4.1/4.0 Level (HP@4.1/4.0) or Main Profile at 4.1/4.0/.3.2/3.1/3.0 Level (MP@4.1/4.0/3.2/3.1/3.0) VC1 - Advanced Profile at Level-3 (AP@L3) or Advanced Profile at Level-2 (AP@L2) Video Frame Size:
1920×1080 29.97 frames interlaced / 59.94 fields (16:9) 1920×1080 25 frames interlaced / 50 fields (16:9) 1920×1080 24 frames progressive (16:9) 1920×1080 23.976 frames progressive (16:9) 1440×1080 29.976 frames interlaced / 59.94 fields (16:9) 1440×1080 25 frames interlaced / 50 fields (16:9) 1440×1080 24 frames progressive (16:9) 1440×1080 23.976 frames progressive (16:9) 1280×720 59.94 frames progressive (16:9) 1280×720 50 frames progressive (16:9) 1280×720 24 frames progressive (16:9) 1280×720 23.976 frames progressive (16:9) 720×480 29.97 frames interlaced / 59.94 fields (4:3/16:9) 720×576 25 frames interlaced / 50 fields (4:3/16:9) Audio Codecs:
Dolby Digital (up to 5.1 channels with a maximum bitrate of 640 Kbit/s) Dolby Digital Plus (up to 7.1 channels with a maximum bitrate of 4.736 Mbit/s) Dolby Lossless (up to 9 channels with a maximum bitrate of 18.64 Mbit/s) DTS (up to 5.1 channels with a maximum bitrate of 1.5244 Mbit/s) DTS HD (up to 9 channels with a maximum bitrate of 24.5 Mbit/s) Linear PCM (up to 9 channels with a maximum bitrate of 27.648 Mbit/s) Subtitles
Image bitmap subtitles (.SUP) Text subtitles (.SRT) Maximum Video Bitrate
40 Mbit/s Maximum Total Bitrate
48 Mbit/s Maximum Data Transfer Rate
54 Mbit/s I highly recommend reviewing the following resources to learn more about Blu-ray specifications and structure:
http://www.hughsnews.ca/faqs/authoritative-blu-ray-disc-bd-faq/4-physical-logical-and-application-specifications https://www.videohelp.com/hd https://forum.doom9.org/showthread.php?t=154533 VideoHelp and doom9 will be your best friends. Use those resources.
I can just toss the Blu-ray specs out there, but understanding is also important. We can blindly click on things, blindly pass arguments...or, make informed actions. Let's talk a little bit about H.264 AVC.
You can think of H.264 as a family of profiles. Each profile has different rules relating to the encoding techniques and algorithms used to compress files.
The Baseline profile is the primary profile used for mobile applications, video conferencing, and low powered devices. It benefits from achieving great compression ratios and other techniques like chrominance sampling and entropy coding techniques.
The Main profile is the primary profile used for standard definition television broadcasts. It benefits from all of the Baseline profile enhancements, in addition to improved frame prediction algorithms.
The High profile is the primary profile used for disc storage and high definition television broadcasts. It benefits from achieving the best compression ratios and using transformation techniques to reduce network bandwidth requirements by up to 50%.
Profiles are proportional to the level of complexity required to encode/decode. Thus, higher complexity profiles require more CPU power.
Levels are another type of configuration to set constraints on the encoder/decoder. The levels are a reflection of history, with H.264 evolving and growing as a standard. While profiles define rules for encoding techniques, levels place maximums on:
Maximum decoding speed (Macroblocks/s) Maximum frame size (Macroblocks) Maximum video bitrate (Kbit/s) There are currently 20 levels, with the lowest level being Level 1 and the highest being Level 6.2.
Level 1 defines constraints of:
Maximum decoding speed of 1,485 Macroblocks/s Maximum frame size of 99 Macroblocks Maximum video bitrate of 64 Kbit/s Level 6.2 defines constraints of:
Maximum decoding speed of 16,711,680 Macroblocks/s Maximum frame size of 139,264 Macroblocks Maximum video bitrate of 800,000 Kbit/s Thus, you arrive at resolutions ranging from 128x96 (Level 1) through 8,192x4,320 (Level 6.2).
Now, when we look back at the Blu-ray specifications, you can use your knowledge of H.264 profiles and levels to choose appropriate encoding techniques and constraints that fall within the spec.
Viewing Media Specifications with MediaInfo
As you might imagine, it is important to always know the specifications of your audio and video. Therefore, having some sort of tool that can quickly show you this information in a presentable manner is an essential tool. There are quite a few tools for this, but one of the most popular ones that I like is MediaInfo. It is free open-source software that is simple to use.
Download and install MediaInfo. Set your View. By default it is Basic. I really like Tree. Open a video or set of videos under File, and that's it! As we can see in this example, the media file I selected uses AVC and was encoded using x264. Things like the frame rate (23.976 Frames/s constant), Bitrate (2,741 Kb/s), resolution (720P), and encoding settings are quickly available. Here are the encoding settings that were used for this file:
cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=8 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=16 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=288 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=14.0 / qcomp=0.60 / qpmin=0 / qpmax=81 / qpstep=4 / ip_ratio=1.40 / aq=3:1.00
In the next tutorial, we will look at ripping from physical media, battling DRM, and destroying senseless region locks.