Ticket #2198 (closed defect: fixed)
Opened 6 years ago
Last modified 6 years ago
Transcode treats some 1080i streams as 1088 and puts a grey line at the bottom after resizing
| Reported by: | wagspat@… | Owned by: | cpinkham |
|---|---|---|---|
| Priority: | minor | Milestone: | 0.21 |
| Component: | mythtv | Version: | head |
| Severity: | low | Keywords: | transcode 1080i |
| Cc: | Ticket locked: | no |
Description
When transcoding and resizing 1080i streams, myth transcode identifies the height of the stream as 1088 pixels, instead of 1080. This causes a grey line to be placed at the bottom of the transcoded image. Transcode is indeed reporting this, and I told my transcode profile to keep the aspect ratio, thus causing the error. For example, here's a message from my logs:
2006-08-15 21:14:56.742 Resizing from 1920x1088 to 960x544
The grey line is a minor issue, but still is a defect.
Attachments
Change History
Changed 6 years ago by wagspat@…
- Attachment 00000041.jpg added
comment:1 Changed 6 years ago by wagspat@…
It looks like the way to solve this may be to call img_resize_full_init instead of img_resize_init in transcode.cpp. This allows the specification of the borders around an image that should be cropped off the image. I'm attaching a patch against the 0.19-fixes branch that seems to work for the 1080i use case here. Hopefully this provides some good direction.
Changed 6 years ago by wagspat@…
- Attachment 1080iTranscode.patch added
preliminary patch that seems to address the 1088 high 1080i feed transcoding issue
Changed 6 years ago by wagspat@…
- Attachment 1080iTranscode.20060821.patch added
updated patch against SVN version 10860
comment:3 Changed 6 years ago by cpinkham
- Status changed from new to closed
- Resolution set to fixed
(In [11462]) When resizing video in the lossy side of mythtranscode, trim off the bottom 8 pixels when we encounter a video file that is 1088 pixels high. These are normally actually only 1080 pixels but need to have 16-pixel high block so there are 8 blank rows of pixels at the bottom of every frame. This patch strips those off and also calculates the new height/width based on 1080 instead of 1088 if the user specified autoheight or autowidth in the transcoding profile settings.
Closes #2198 by applying slightly modified patch by wagspat.

Example frame showing the 4px grey line at bottom (scaled down from 8px because all dimensions were halved)