Hello!
I'm a VERY new newbie to ExifTool and the forum. It is possible that I am simply misreading the ExifTool output, so I'm wondering if someone can help me out with this.
I have a sample DNXHD 36 MXF OP1A video file. When I bring the file into DaVinci Resolve and go to the head of the clip, the Start Timecode is 19:48:23:00. However, when I look at the file's metadata using ExifTool, it tells me that the Start Timecode is 19:49:34:00. What could be the reason for this discrepancy?
I am launching ExifTool by dragging the video file onto the exiftool(-k).exe in Explorer on Windows 10.
Thanks to anyone who's able to take the time to help me out with this!
-Justin
What is the output of
exiftool -time:all -g1 -a -s FILE
Just copy/paste the output, don't screenshot it.
Here's the output for the file in question:
---- System ----
FileModifyDate : 2016:09:27 00:33:48-04:00
FileAccessDate : 2020:07:26 16:43:19-04:00
FileCreateDate : 2020:07:24 22:10:39-04:00
---- MXF ----
ContainerLastModifyDate : 2016:09:27 04:21:46.812
CreateDate : 2016:09:27 04:21:47.128
PackageLastModifyDate : 2016:09:27 04:21:47.128
CreateDate : 2016:09:27 04:21:46.812
PackageLastModifyDate : 2016:09:27 04:21:46.812
ModifyDate : 2016:09:27 04:21:46.812
Thank you!
Hmmm... I had assumed from the name that it might have been part of the Time group, but I guess not. I don't have any experience with the MXF format.
What's the output of this command? Hopefully it's not too long due to the wildcards.
exiftool -g1 -a -s -StartTime* -*Duration* FILE
That command gave me:
---- Track1 ----
Duration : 0:11:32
---- Track2 ----
Duration : 0:11:32
---- Track3 ----
Duration : 0:11:32
StartTimecode : 19:49:34
Duration : 0:11:32
Duration : 0:11:32
StartTimecode : 19:49:34
Duration : 0:11:32
---- Track4 ----
Duration : 0:11:32
---- Track5 ----
Duration : 0:11:32
---- MXF ----
Duration : 0:11:32
UPDATE:
I transcoded the file into an Apple ProRes QuickTime and now ExifTool outputs the correct Start Timecode.
Could this be a bug for reading files with an MXF wrapper?
StartTimecode is stored in units of the EditRate. What is this for your file?
Use the -n option to see the raw count. Multiply this by the EditRate to get the TimecodeStart in seconds.
ExifTool converts this to HH:MM:SS format if it is greater than 30 sec. It isn't in the time group because generally timecodes don't represent clock times.
- Phil
Wow the maestro himself! Thanks for taking the time!
The EditRate is 23.97602398 (which I'm guessing is just the exact value for 23.98fps).
This is the output of exiftool -g1 -a -s -n -StartTime* -*Duration* FILE for the original DNXHD 36 MXF file:
---- Track1 ----
Duration : 692.400041551844
---- Track2 ----
Duration : 692.400041551844
---- Track3 ----
Duration : 692.400041551844
StartTimecode : 71374.3029881638
Duration : 692.400041551844
Duration : 692.400041551844
StartTimecode : 71374.3029881638
Duration : 692.400041551844
---- Track4 ----
Duration : 692.400041551844
---- Track5 ----
Duration : 692.400041551844
---- MXF ----
Duration : 692.400041551844
This is the output of the same command executed on a transcoded version of the file that is an Apple ProRes 422 QuickTime:
---- QuickTime ----
Duration : 692.400041666667
PreviewDuration : 0
SelectionDuration : 0
---- Track1 ----
TrackDuration : 692.400041666667
MediaDuration : 692.400041666667
---- Track2 ----
TrackDuration : 692.400041666667
MediaDuration : 692.400041666667
---- Track3 ----
TrackDuration : 692.400041666667
MediaDuration : 692.400041666667
---- UserData ----
StartTimecode : 19:48:23:00
StartTimeScale : 24000
StartTimeSampleSize : 1001
---- XMP-xmpDM ----
StartTimeScale : 24000
StartTimeSampleSize : 1001
DurationValue : 16617601
DurationScale : 4.16666666666667e-005
StartTimecodeTimeFormat : 23976Timecode
StartTimecodeTimeValue : 19:48:23:00
Why might these outputs be different?
Thanks!
Well, the new file shows a time scale of 24 fps (StartTimeScale). But the old file shows 23.97602398 (EditRate).
This is exactly the difference between the StartTimeCode values:
19:49:34 = 19:48:23:00 * 24 / 23.97602398
Can you show me the output from exiftool -a -g1 -s on the original file? I'm wondering where the 24 fps came from.
- Phil
Sure! This is for the original MXF file:
---- ExifTool ----
ExifToolVersion : 12.01
---- System ----
FileName : BTBD-ASN_S038_S001_T018.mxf
Directory : G:/py_scripts/vfx_import/test_media/mxf
FileSize : 3.4 GB
FileModifyDate : 2016:09:27 00:33:48-04:00
FileAccessDate : 2020:07:27 15:04:01-04:00
FileCreateDate : 2020:07:24 22:10:39-04:00
FilePermissions : rw-rw-rw-
---- File ----
FileType : MXF
FileTypeExtension : mxf
MIMEType : application/mxf
---- MXF ----
MXFVersion : 1.2
ObjectModelVersion : 1
SDKVersion : 1.2
ContainerLastModifyDate : 2016:09:27 04:21:46.812
PackageName : Source Package
CreateDate : 2016:09:27 04:21:47.128
PackageLastModifyDate : 2016:09:27 04:21:47.128
SampleRate : 23.97602398
CreateDate : 2016:09:27 04:21:46.812
PackageLastModifyDate : 2016:09:27 04:21:46.812
EssenceStreamID : 2
IndexStreamID : 1
ApplicationSupplierName : Adobe Systems Incorporated
ApplicationName : Adobe Media Encoder
ApplicationVersionNumber : 1.0.0.0 released
ApplicationVersionString : 10.4.0
ApplicationPlatform : win32
ToolkitVersion : 4.5.12.0 patched
ModifyDate : 2016:09:27 04:21:46.812
Duration : 0:11:32
---- Track1 ----
PresentationAspectRatio : 1.777777778
FrameLayout : 0
HorizontalSubsampling : 2
SampledHeight : 1080
SampledWidth : 1920
DisplayHeight : 1080
DisplayWidth : 1920
ImageHeight : 1080
ImageWidth : 1920
SampleRate : 23.97602398
EssenceLength : 0:11:32
VideoLineMap : 2 4 42 0
VerticalSub-sampling : 1
ComponentDepth : 8
ImageAlignmentOffset : 8192
LinkedTrackID : 512
TrackNumber : 352390144
TrackID : 512
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : Picture Essence Track
Duration : 0:11:32
---- Track2 ----
AudioReferenceLevel : 0
SampleRate : 48000
EssenceLength : 0:11:32
LockedIndicator : True
BitsPerAudioSample : 24
ChannelCount : 2
AudioSampleRate : 48000
BlockAlign : 6
AverageBytesPerSecond : 144000
DialNorm : 0
LinkedTrackID : 768
TrackNumber : 369164544
TrackID : 768
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : Sound Essence Track
Duration : 0:11:32
---- Track3 ----
TrackNumber : 0
TrackID : 0
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : SMPTE 12M Timecode Track
Duration : 0:11:32
DropFrame : False
RoundedTimecodeTimebase : 24
ComponentDataDefinition : SMPTE 12M Timecode Track
StartTimecode : 19:49:34
Duration : 0:11:32
TrackNumber : 0
TrackID : 0
TrackName : Timecode
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : SMPTE 12M Timecode Track
Duration : 0:11:32
DropFrame : False
RoundedTimecodeTimebase : 24
ComponentDataDefinition : SMPTE 12M Timecode Track
StartTimecode : 19:49:34
Duration : 0:11:32
---- Track4 ----
TrackNumber : 0
TrackID : 1
TrackName : Track 1
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : Picture Essence Track
Duration : 0:11:32
---- Track5 ----
TrackNumber : 0
TrackID : 2
TrackName : Track 2
EditRate : 23.97602398
Origin : 0 s
ComponentDataDefinition : Sound Essence Track
Duration : 0:11:32
---- Composite ----
ImageSize : 1920x1080
Megapixels : 2.1
Well, RoundedTimecodeTimebase is 24 fps. I'll have to re-read the MXF specification, but I should have been going by the spec when I decided to use EditRate in the calculation. I don't know why the other apps seem to be using a rounded timescale.
- Phil
Interesting...well for my project transcoding to QuickTimes first is an acceptable workaround. Thanks so much for looking into it!
-Justin