The converted file is very slow after dragging the progress bar

[5UFKEFU]

Using the following command, you can see that the keyframes are very regularly spaced every 33 frames. ffprobe -select_streams v:0 -show_frames -show_entries frame=pict_type -of csv input.mov | grep -n 'I' | cut -d ':' -f 1

1
33
65
97
129
161
193
225
257
289
321
353
385
417
449
481
513
545
577
609
641
673
705
737
769
801
833
865
897
929
961
993
1025

follow command show：moov before mdat.

mp4box -info MARVELS\ IRON\ MAN\ 3\ -\ BLU-RAY\ 3D_AVP.mov

[iso file] Unknown box type vexu in parent hvc1
[iso file] Unknown box type hfov in parent hvc1
# Movie Info - 4 tracks - TimeScale 2400
Duration 02:22:23.223
Fragmented: no
Progressive (moov before mdat)
Major Brand qt   - version 512 - compatible brands: qt  
Created: GMT Sun May 12 06:36:25 2024


Chapter Track:
	#1 - 00:00:00.000 - "Chapter 01"
	#2 - 00:04:52.751 - "Chapter 02"
	#3 - 00:07:55.433 - "Chapter 03"
	#4 - 00:12:12.440 - "Chapter 04"
	#5 - 00:19:04.101 - "Chapter 05"
	#6 - 00:23:47.885 - "Chapter 06"
	#7 - 00:29:47.703 - "Chapter 07"
	#8 - 00:39:46.384 - "Chapter 08"
	#9 - 00:45:56.045 - "Chapter 09"
	#10 - 00:59:19.639 - "Chapter 10"
	#11 - 01:01:56.922 - "Chapter 11"
	#12 - 01:09:24.452 - "Chapter 12"
	#13 - 01:18:41.508 - "Chapter 13"
	#14 - 01:23:52.945 - "Chapter 14"
	#15 - 01:37:55.995 - "Chapter 15"
	#16 - 01:56:18.305 - "Chapter 16"
	#17 - 01:59:38.755 - "Chapter 17"

Meta-Data Tags:
	tool: GPAC-2.4-revrelease

# Track 1 Info - ID 1 - TimeScale 2400
Media Duration 02:10:32.875 
Track has 1 edits: track duration is 02:10:32.875
Track composition offset shift (negative CTS offset): 204
Track flags: Enabled In Movie In Preview Size is AspectRatio
Media Samples: 187801
Visual Track layout: x=0 y=0 width=1920 height=1080
Media Type: vide:hvc1
	Visual Sample Entry Info: width=1920 height=1080 (depth=24 bits)
	HEVC Video - Visual Size 1920 x 1080
	HEVC Info: Profile Main 10 @ Level 4 - Chroma Format YUV 4:2:0

	NAL Unit length bits: 32 - general profile compatibility 0x20000000

	Parameter Sets: 1 VPS 1 SPS 1 PPS 
	SPS resolution 1920x1080
	Bit Depth luma 10 - Chroma 10 - 1 temporal layers
	VPS#1 hash: 154C6C8AD2550609B8F1C387A91B029379047CAF
	SPS#1 hash: D5CD901536EBD730807D2B3C2C50D7D91BFEB632
	PPS#1 hash: 427C9C7AD14AF37E8DF4541BD1A8D479206059FA

	LHVC Info:
	NAL Unit length bits: 32
	Parameter Sets: 1 SPS 1 PPS 
	SPS resolution 1920x1088
	1 temporal layers
	HEVC base layer - Complete representation 0
	SPS#1 hash: 04EC58406BBECB8578349603A7DE68F9AF5577ED
	PPS#1 hash: 95AFDAAA3E19AE86B301A4664274E57B53149B5B
	RFC6381 Codec Parameters: hvc1.2.4.L120.B0
	Only one sync sample
	Max sample duration: 104 / 2400

# Track 2 Info - ID 2 - TimeScale 48000
Media Duration 02:10:32.874 
Track has 1 edits: track duration is 02:10:32.875
Track flags: Enabled In Movie
Media Samples: 375977984 - CFR 48000/sec
1 UDTA types: 
	name: Surround 7.1
Alternate Group ID 1
Media Type: soun:in24
	PCM Audio Sample Rate 48000 8 channel(s) 24-bits little-endian
	RFC6381 Codec Parameters: in24
	All samples are sync
	Max sample duration: 1 / 48000

# Track 3 Info - ID 3 - TimeScale 1000
Media Duration 02:10:32.867 
Track has 1 edits: track duration is 02:10:32.866
Track flags: Disabled In Movie
Media Samples: 17
Media Type: text:text
	QT/3GPP text
	Size 0 x 0 - Translation X=0 Y=0 - Layer 0
	RFC6381 Codec Parameters: text
	All samples are sync
	Max sample duration: 1102310 / 1000

# Track 4 Info - ID 4 - TimeScale 90000
Media Duration 02:22:23.223 
Track flags: Enabled In Movie In Preview
Media Samples: 2171
Media Type: subp:mp4s
	RFC6381 Codec Parameters: mp4s.E0
	All samples are sync
	Max sample duration: 67107840 / 90000