I am writing to you (especially to the developers of the program) to ask for a little “help” and clarification of a technical nature:
I have recently saved on my PC a Blu-Ray encoded with the program “MakeMKV” with these characteristics:
Video MKV
ID : 1 ID in the original source medium : 4113 (0x1011) Format : AVC Format/Info : Advanced Video Codec Format profile : High@L4.1 Format settings : CABAC / 4 Ref Frames Format settings, CABAC : Yes Format settings, Reference frames : 4 frames Codec ID : V_MPEG4/ISO/AVC Duration : 3 h 1 min Bit rate mode : Variable Bit rate : 22.4 Mb/s Maximum bit rate : 35.0 Mb/s Width : 1 920 pixels Height : 1 080 pixels Display aspect ratio : 16:9 Frame rate mode : Constant Frame rate : 29.970 (30000/1001) FPS Standard : NTSC Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : MBAFF Scan type, store method : Interleaved fields Scan order : Top Field First Bits/(PixelFrame) :* 0.361 Stream size : 28.5 GiB (79%) Language : English Default : No Forced : No Color range : Limited Color primaries : BT.709 Transfer characteristics : BT.709 Matrix coefficients : BT.709 Original source medium : Blu-ray
Now as you can see from the highlighted text, the video scan type is “MBAFF” Interleaved fields - Top Field First!
Searching around the Web, I found this page that gives the definition of MBAFF, or “Macroblock-Adaptive Frame/Field Coding” =
From what I understand, it looks to me like an evolved version of the interlacing possible with H.264 encoding… but it still remains unclear to me!
At this point, wanting to enhance the video with TVAI, I was wondering if this type of video should be made to digest the program as “Interlaced” video or as “Interlaced Progressive” when choosing the scan type!
H.264 encodes in 16x16 macroblock units, but MBAFF detects interlaced stripes in macroblock units and encodes blocks with few stripes in progressive mode.
Previously, only PAFF (Picture Adaptive Field Frame) could be used, but MBAFF has been added to improve compression efficiency.
Decoded frames are interlaced.
For “Interlaced”, FFMPEG’s built-in filter (bwdif) separates the Top and Bottom fields from 30i and converts them to 60p.
The “Interlaced Progressive” filter does not do any processing, and the TVAI filter can only select Dione and Iris.
“Interlaced Progressive”, generally speaking, there are two ways to think of it. One is that the video that should be encoded as interlaced is encoded as progressive (with stripes).
The other is a 30p video encoded as 30i for playback in NTSC (Top and Bottom are the same. No stripes).
If it is the first, have to force the field separation process in, and if it is the second, have to force it to be treated as a progressive, but it is neither, so not sure what want with "Interlaced Progressive " is not quite sure what want to do.
At this point I ask you who are well-informed: for the AVC MBAFF video format that I want to convert with TVAI, is it correct to work it as “interlaced” video for all intents and purposes, duplicating the framerate? Is it still remains a “progressive” video signal?
This is a very interesting topic. never heard of MBFF before. would be interesting to see what DEVs have to say about it. only thing I can say is, since it is a high quality video already, avoid Iris as much as possible.
here is my take on things: if it should be treated as Interlace I would only use Dione:DV, nothing else.
If it is to be treated as Progressive scan video, Use Gaia HQ.
I have tried encoding the video in question with both the “Iris” model and the “Dione DV” model… and I must say that in “manual” mode and with Detail Recovery at value 20, the result is still better than the normal “Dione DV”.
sorry I didn’t get any response from anyone on the team… but I can almost assure you that this video format can be considered for all intents and purposes as interlaced video: I have tried both various video players and other encoding programs… and if you don’t turn deinterlacing on, the video quality decays… so I confirm that you can ecode this format as interlaced video!
Thanks for uploading. I ran some test exports using all three modes and I would agree that Interlaced mode is the best option for MBAFF files. It seems that the Progressive mode causes some ghosting effects during fast motion (drumming especially).
