Capture resolution problem with CasparCG 2.4 server and decklinkcard

I noticed that captured image quality with 2.1 is better then with 2.4 version.
This only seems the case with HDCAM 1080i50 MXF capture.
Capture in MP4 format seems fine.

Vertical resolution seems reduced with 2.4 version with capture in HDCAM 1080i50 format (TV broadcast) (MXF)

Steps to repro
I used these commands with CasparCG 2.1 to capture from a decklinkcard

1.Setup with CasperCG 2.1
SET 1 MODE 1080i5000
PLAY 1-1 Decklink 1 FORMAT 1080i5000 CHANNEL_LAYOUT stereo
record file with
ADD 1 FILE “Testclip HD.mxf” -b 50000000 -acodec pcm_s24le -vcodec mpeg2video -pix_fmt yuv422p -alternate_scan 1 -g 12 -bf 2 -minrate 50000k -maxrate 50000k -color_primaries bt709 -color_trc 1 -colorspace 1 -dc 10 -lmin 1*QP2LAMBDA

Setup with CasperCG 2.4
SET 1 MODE 1080i5000
PLAY 1-1 Decklink 1 FORMAT 1080i5000
record file with
ADD 1-700 FILE “TEST 2.4 NRK.mxf” -b:v 50000000 -codec:a pcm_s24le -codec:v mpeg2video -filter:v interlace,zscale=rangein=full:range=limited:primaries=709:transfer=709:matrix=709,format=yuv422p -alternate_scan:v 1 -g:v 12 -bf:v 2 -minrate:v 50000k -maxrate:v 50000k -color_primaries:v bt709 -color_trc:v 1 -colorspace:v 1 -filter:a pan=stereo|c0=c0|c1=c1

2 feed a HD SDI 1080i50 (TV broadcast) to the SDI input of the Decklink card, use the CasparCG test picture for playback

2.Capture from a Decklink HD SDI source in HDCAM 50 mode with CasparCG 2.1 and Caspar 2.4

compare the image quality between CasparCG 2.1 capture and CasparCG2.4 capture
vertical resolution has decreased with CasparCG 2.4 capture

Here the results, captured image of CG2.4 has reduced vertical resolution.



I’m gonna report this on github too.