How to edit a portion of Blu-ray video without transcoding in Encore

[cheerful]

The task:

You want to edit a portion of H.264 Blu-ray video used in Encore (let's call it segment B) but you don't want Encore to transcode the rest of the video (let's call it A before B and C after B).

Some would suggest you split the video, edit B, and put all segments on a timeline. However, Encore will produce 3 m2ts file, 1 for each segment. The Blu-ray player may have a significant pause between the segments. It might not be acceptable, depending on the scenes.

If you simply edit B, and then join with A and C, Encore will transcode the entire video. The quality drop may not be acceptable.

I'm describing a solution here. Credit should go to poisondeathray. Without his help, this would never be possible.

Tools:
Adobe Premiere (editing software)
Adobe Encore (Blu-ray authoring)
tsMuxer (muxing and join, "Insert SET and VUI data if absent" and "Continually insert SPS/PPS" must be off)
A splitter (VideoRedo or alike)

Steps

1. Split the video and save segments A, B, C. The split must be done at GOP boundary. In my case, I'd have to mux video and audio first as the tool does not work well with elementary stream.

2. Do all the editing you want on B

3. Cut the last 3 GOP from A (A3) and the first 3 GOP from C (C3). I've also tried just 1 GOP but it may fail to join or Encore may not like it. I did not try 2 GOP. If want to know why, see additional notes below

4. In the timeline, put A3 before B and C3 after B. You have to force the encoder (AME) to create key-frame (I-frame) at these boundaries. Chapter marker can help. But it does not always work if it's not right at a scene change. You can apply effect such as noise on A3 or C3 to help.

5. Encode in AME, mux, and split to cut out the segment you need (B1). Verify key-frame at the boundary.

6. tsMuxer to join A, B1 and C.

7. Import into Encore. Should get "Don't transcode"

Additional notes

N1. The 2 tsMuxer options mentioned above will messed up the join (playback issue or Encore transcoding). They are on by default. So remember to turn them off.

N2. Without flanking A3 and C3, the AME output will can join with A and C. However ,the output will require transcoding in Encore. The exact reason is unknown. Changing GOP settings and bitrate does not appear to make a difference

N3. If B and B1 has the exact same length, the final output may have exact same length as the original. In my case, the final 2 frams disappeared. It has no impact in my project but it's strange.

N4. The audio in the last part (C) in the final output might be out of sync. I don't know the exact reason. But I have to adjust mine by a few frames.

[aedipuss]

sounds kind of silly. if it's no re-code video pp will only re-code the portions that are changed. put it on the timeline and cut/paste all you want. if that doesn't work convert it all to lossless avi and edit that.

[poisondeathray]

sounds kind of silly. if it's no re-code video pp will only re-code the portions that are changed. put it on the timeline and cut/paste all you want. if that doesn't work convert it all to lossless avi and edit that.

The background context was he no longer had the original 1st generation project files. But there was "media offline" for one of the segments, only to be discovered at a later date. So he wanted to "fix" that section, without having to re-encode the entire BD which is already 2nd generation.

You can join it no problems for playback in media players, and for "normal" usage - but not for BD passthrough. And there are problems with glitches at the seams in encore unless it's done properly.

Encore won't accept a joined "middle section" for passthrough that has a startcode. So the usual steps would be encode a "replacement" section using the same encode settings - well that won't work because it has a startcode. That's the reason for encoding a few GOP's on either sides, only to cut out later. Also if using tsmuxer, the you must have "do not change SEI and VUI data", and uncheckmark insert SPS/PPS for BD . Also important is to use similar bitrates (or go slightly lower), otherwise you will have a VBV violation

I believe there were issues with his original cuts, because they were already missing 2 frames when joined, or separately added up before doing the procedure - this suggests an issue with splitting, maybe an issue with the original stream. So when the sections were joined they added up perfectly to the immediate source, which had 2 missing frames.

[cheerful]

sounds kind of silly. if it's no re-code video pp will only re-code the portions that are changed. put it on the timeline and cut/paste all you want. if that doesn't work convert it all to lossless avi and edit that.

I have tried that with VideoRedo, inserting just the middle segment and use smart re-encode. The result is rejected by Encore