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Feature #509

Idea: Online Cutting Function

Added by renne - over 13 years ago. Updated over 12 years ago.

Status:
Rejected
Priority:
Normal
Assignee:
Category:
PVR / DVR
Target version:
Start date:
2011-05-12
Due date:
% Done:

0%

Estimated time:

Description

Currently you have to download the complete recordings with all advertisement, etc.

Online-cutting can reduce the amount of download data up to 50%**.

How it can work:

After switching to the online-cutting-dialog of a recording in the web-ui,

  1. the web-ui creates a thumbnail-timeline of the recording (one thumbnail per minute)
  2. the user presses a button between two thumbnails to set a mark
  3. the web-ui creates a thumbnail-timeline of the recording (one thumbnail per second of selected minute)
  4. the user presses a button between two thumbnails to set a mark
  5. the web-ui creates a thumbnail-timeline of the recording (one thumbnail per frame of selected second)
  6. the user presses a button between two thumbnails to set a frame exact mark
  7. TVHeadEnd stores UNIX-timestamp, seconds since start of recording, frame-number of current second and Presentation-Timestamp of the mark in the XML-Metadata of the MKV-file

The exponential selection of frames provides a fast and simple setting of marks.

When the user presses the "Cut now" button, TVHeadEnd creates a cutted copy of the recording by:

  • hardlinking complete or closing GOPs in the filesystem
  • reencoding starting truncated GOPs
    OR
  • reencoding the marked parts of the recording

Best regards,

Renne

History

#1

Updated by piotr galek over 13 years ago

I think better is mark over uniqe event in stream like change audio from 5.1 to stereo when in movie start show advertisement.

Best solution for this have MythTV (in 99% hit good in advertisement and mark)
Please check

http://www.mythtv.org/wiki/Commercial_Detection

Methods

Blank Frame Detection - Is used to determine when a programme fades to black (this invariably happens between show segments)
Blank Frame & scene change detection - As above but tries to determine that a large amount of the picture has changed
Scene change detection - Tries to determine that a large amount of the picture has changed
Logo detection - Looks for a part of the picture that does not change during a recorded show - i.e. an onscreen logo. Logos are usually removed for the duration of commercial breaks, making them 'easier' to spot.
All - Use all commercial detection methods at the same time. This detection method uses information from blank-frame, scene change, and logo detection and can easily be modified to take advantage of other detection information. It works in a fundamentally different way than the normal blank-frame and scene change methods. The code groups the frames into blocks separated by blank frames and rates each block based upon several factors such as the rate of scene change, what percentage of frames in the block have a logo present, how long/short the block is, etc.. Indications that a block is part of a commercial (such as very high rates of scene changes) lower the block's score, while indications that a block is part of the show (such as having a logo present on most frames) raise the block's score. In the end the blocks are looked at as a group and various bits of logic applied to make the final determination where commercials start and end. On most of the shows tested, this method seems to be doing a much better job than just blank-frame or blank-frame plus scene-change.
#2

Updated by renne - over 13 years ago

piotr galek wrote:

Best solution for this have MythTV (in 99% hit good in advertisement and mark)

Automatic detection systems are not reliable, but a nice preliminary stage. TV stations try to manipulate the video stream in a way to make automatic detection systems fail. It's just another hare and tortoise game. So you need the manual process anyway to adjust falsely detected marks.

Additionally, the system can fingerprint the frames and check three minutes before a opening mark and three minutes after a closing mark for overlapping video.

#3

Updated by renne - about 13 years ago

renne - wrote:

When the user presses the "Cut now" button, TVHeadEnd creates a cutted copy of the recording by:

  • hardlinking complete or closing GOPs in the filesystem
  • reencoding starting truncated GOPs
    OR
  • reencoding the marked parts of the recording

Luckily, mkvmerge has a "--split" option. TVHE just has to pass the timecodes to mkvmerge to do frame exact splitting into several files at the timecodes.

#4

Updated by Adam Sutton over 12 years ago

  • Status changed from New to Rejected

I don't think this is likely to happen any time soon, so I'm going to remove it. However please feel free to re-submit if you really want to include it. But I think ultimately this would be better suited to a post processing script.

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