Fanres - THE ORIGINAL Fan Restoration Forum

disc.blue is a new free open file-based format; main idea is to release a single audiovideo file that could be eventually recorded on a physical optical disc, along with artworks for cover and disc (and eventual booklet) and other info.

• What kind of "format" this would be?

Something a bit like DTS Audio CD (that uses Compact Disc as disc format) or SACD (that uses DVD as disc format) or AVCHD (that can use DVD, BD, or other physical formats); Blu-ray and Ultra HD Blu-ray are file formats that use Blu-ray disc as disc format - but for example you can burn BD (or even UHD-BD) structure on a DVD-9 or even DVD-5 (albeit the former is no more BD compliant since 2011, and the latter never was) and some BD/UHD-BD players can play them.

• Why a new "format"? Aren't DVD/BD/UHD-BD enough?
  

• Yes, they are; still there are some reasons to not use them:
  • they do not allow 44.1kHz - absolute must for LD and Cinema DTS untouched audio tracks
    
  • they do not allow 2K/4K - needed for DCI contents, even if they are (still?) quite rare
    
  • not all players can play burned discs - especially BD and UHD-BD
    
  • format structures and file format take space - at least around 7% for BD compared to MKV
    

So, if you want to preserve an untouched 44.1kHz audio track and/or get DCI 2K/4K video and/or burn a file that may be compatible with an hardware player, but will be surely compatible with ALL computers with proper player and/or want to put more data onto an optical disc, then you can't use DVD/BD/UHD-BD

• Then why not using an existing file format, like AVCHD or XAVC?
  

Because they have some limitations - mainly no 44.1kHz and DCI 4K; albeit XAVC allows 4K, it does not allow AV1 or VP9, nor Opus, Vorbis, Flac.

• So at the end it will be just an MKV container eventually burned on optical disc?
  

Basically yes; but there will be some rules to follow; mainly file size (to fit on disc), types of container/video codec/audio codec/video resolution/audio sample frequency/video encoding settings/audio encoding settings; still, less constrained than DVD/BD/UHD-BD file formats!

• What's the main point of all of this?
  

To set a standard, using free open codecs, that project makers can follow to produce a file that is not only compatible with all software players, but also with the vast majority of hardware media players; even if the file burned on disc would be compatible only with computer-based systems - using Intel or AMD CPUs, it could always be retained as the original copy: BD-R could last several hundred years, if not thousand, at the contrary of any HDD that may last a decade or two, or SSD/USB and other memories that last only few years, as some of you could have experienced directly... the fact that optical disc could not be read anymore in hundred years is off topic here.

• Which physical optical disc?
  

As you can guess from the format name, main optical disc used should be Blu-ray; but DVD can be taken in account for shorter programs and/or low resolution
For example, DVD-R/+R for SD or short HD content; BD-R 25/50GB for HD or 4K UHD content; BD-R 100/128GB for 8K UHD or long 4K UHD content.

• Which container?
  

MKV for video and MKA for audio; it's free, it's the most popular and it should be played by almost all hardware and software media players.

• Which video codecs?
  

AV1 and VP9, as they are free and open; the former allows more than 30% bitrate saving compared to HEVC, while the latter is included mostly for compatibility reason; AV2 will be included as soon as it will be available; do note also that AV1 has a very interesting feature regarding restoration: grain synthesis.

• Which video settings?
  

• These are the proposed video settings:
  • Display aspect ratios: 16:9, 17:9
    
  • Resolutions: 4320p, 2160p, 1080p, 720p, 540p, 360p, 270p
    
  • Picture aspect ratios: 21:9 (scope), 18:9 (Univisium), 17:9 (1.89:1), 1.85:1 (flat), 16:9 (1.78:1), 15:9 (1.66:1), 12:9 (1.33:1)
    
  • Framerates: 23.976, 24, 25, 29.97, 30, 48, 50, 59.94, 60
    
  • Scan mode: progressive
    
  • Bit depths: 8bit, 10bit
    
  • Chroma subsampling: 4:2:0
    
  • Grain synthesis: supported with AV1
    
  • Maximum bitrate (audio/video combined): 64mbps (BD-R 25/50GB), 80mbps (BD-R 100/128GB)
    

• Which audio codecs?
  

FLAC as lossless, and Opus and Vorbis as lossy; old AC-3 and DTS could be used too, as their patents are expired, but their use is not encouraged.

• Which audio settings?
  

• These are the proposed audio settings:
  • Channels: 8 (max)
    
  • Sampling frequencies: Opus, Vorbis 48kHz; others 44.1kHz, 48kHz, 96kHz
    
  • Bit depths: 16bit; 24bit
    
  • Immersive audio: in progress
    

• Which subtitles types?
  

SRT and SSA, and others that are free, open, and compatible with MKV.

• Which file name conventions?
  

To be decided yet; but something very similar to DCI.

Wanna check provisional video compliant settings? Visit the spoRv gauge calculator