Opened 13 years ago

Closed 13 years ago

#2198 closed defect (fixed)

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 (3)

00000041.jpg (103.2 KB) - added by wagspat@… 13 years ago.
Example frame showing the 4px grey line at bottom (scaled down from 8px because all dimensions were halved)
1080iTranscode.patch (2.5 KB) - added by wagspat@… 13 years ago.
preliminary patch that seems to address the 1088 high 1080i feed transcoding issue
1080iTranscode.20060821.patch (4.5 KB) - added by wagspat@… 13 years ago.
updated patch against SVN version 10860

Download all attachments as: .zip

Change History (6)

Changed 13 years ago by wagspat@…

Attachment: 00000041.jpg added

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

comment:1 Changed 13 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 13 years ago by wagspat@…

Attachment: 1080iTranscode.patch added

preliminary patch that seems to address the 1088 high 1080i feed transcoding issue

Changed 13 years ago by wagspat@…

updated patch against SVN version 10860

comment:2 Changed 13 years ago by cpinkham

Milestone: 0.21
Version: 0.19head

comment:3 Changed 13 years ago by cpinkham

Resolution: fixed
Status: newclosed

(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.

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