gdigrab captures a single frame, then closes

I'm currently attempting to capture desktop footage in order to post-process it with mpv via vapoursynth and display it back to the screen. In order to do so, I'm using gdigrab (via ffmpeg) to capture a specific window. However, whenever I attempt it, the window shows a single frame of footage, then closes shortly after.

Important Information

Provide following Information:

• mpv version: 0.32.0-94-ge162bcb5a0
• Windows Version: Windows 10, latest version
• Source of the mpv binary: Shinchiro's Windows builds for mpv, Zeranoe for ffmpeg

Reproduction steps

Run mpv av://gdigrab:title="Title of the window" or mpv av://gdigrab:desktop.

Expected behavior

mpv is expected to capture the footage from the selected application, then display it back and apply the Vapoursynth filter if applicable.

Actual behavior

mpv captures a single frame, displays it for under a second, then exits.

Log file

mpv_error_2.log.txt

Some particular lines that were of my interest:

[vd] Codec list:
[vd]     bmp - BMP (Windows and OS/2 bitmap)
[vd] Opening decoder bmp
[vd] No hardware decoding requested.
[vd] Using software decoding.
[vd] Detected 4 logical cores.
[vd] Requesting 5 threads for decoding.
[vd] Selected codec: bmp (BMP (Windows and OS/2 bitmap))
[vf] User filter list:
[vf]   (empty)
[cplayer] Starting playback...
[vd] DR failed - disabling.
[ffmpeg/demuxer] gdigrab: Failed to capture image (error 6)
[lavf] error reading packet: I/O error.
[lavf] EOF reached.
[vd] Decoder format: 1920x1080 [0:1] bgra auto/auto/auto/auto/auto CL=unknown
[vf] [in] 1920x1080 bgra rgb/bt.709/srgb/full/display SP=1.000000 CL=mpeg1/jpeg
[vf] [userdeint] 1920x1080 bgra rgb/bt.709/srgb/full/display SP=1.000000 CL=mpeg1/jpeg
[vf] [userdeint] (disabled)
[vf] [autorotate] 1920x1080 bgra rgb/bt.709/srgb/full/display SP=1.000000 CL=mpeg1/jpeg
[vf] [autorotate] (disabled)
[vf] [convert] 1920x1080 bgra rgb/bt.709/srgb/full/display SP=1.000000 CL=mpeg1/jpeg
[vf] [convert] (disabled)
[vf] [out] 1920x1080 bgra rgb/bt.709/srgb/full/display SP=1.000000 CL=mpeg1/jpeg
[vf] filter input EOF
[ffmpeg/demuxer] gdigrab: Failed to capture image (error 6)
[vf] filter output EOF
[lavf] error reading packet: I/O error.
[ffmpeg/demuxer] gdigrab: Capturing whole desktop as 1920x1080x32 at (0,0)
[lavf] Could not set AVOption user_agent='libmpv'
[lavf] Could not set AVOption tls_verify='0'
[lavf] Could not set AVOption icy='1'
[lavf] Could not set AVOption timeout='60000000'
[cplayer] Set property: shared-script-properties -> 1
[ffmpeg/demuxer] gdigrab: Stream #0: not enough frames to estimate rate; consider increasing probesize
[lavf] avformat_find_stream_info() finished after 0 bytes.

I have already tried using a large value --demuxer-lavf-probesize (in order to increase the amount of bytes probed (around 1920x1080x32x2 = 132710400 to be absolutely safe), as it might be sampling a single frame and declaring it a standalone bitmap file, but the change didn't seem to fix the issue.

Sample files

N/A

Start by reproducing mpv av://gdigrab:title="Title of the window" and mpv av://gdigrab:desktop, then inspect the linked log around the gdigrab error 6 and EOF messages. Trace how mpv handles the gdigrab stream after its first frame; done means continuous capture remains open and displays successive frames.