Suggestions for MKV files

[BogdanH]

Hi Phil,

It's the first time I've tried Exiftool (v8.21) on MKV file and noticed following (compared to other MKV tools):

1. Exiftool lists Chapter data inside "common" Matroska section. Usually, Chapters are listed/viewed as separate section (usually named Chapters or Menu) -which I find better.

2. ChapterTimeStart hour value is wrong in all cases except if it's complete value is zero. For example
RealValue Displayed

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00:00:00  0s
00:20:00  333333:20:00
00:40:00  666666:40:00
01:00:00  1000000:00:00
01:20:00  1333333:30:00 ..etc.
Maybe important: I don't set/use ChapterTimeEnd values when creating chapters for MKV.

3. For TrackType "Video":
-it would be very usefull, if some other important data would be shown.. at least:
e.g.Name = e.g.Value

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FormatProfile=High@L4.1
FormatReFrames=4 frames
BitRate=8171 kbps
Duration=02:41:00 (must be here in case more video tracks are inside MKV)
I don't know, how to decode those values (seen in some other tools), but they are of great value.
Btw. I suggest displaying VideoFrameRate value on up to three decimal points (23,976 instead of 23,98) -it is important.

4. For TrackType"Audio":
-it would be usefull, if following important data would be shown:

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Duration=02:41:00 (in case MKV contains several audio tracks)
BitRate=640 kbps
BitRate=Constant (because MP3 can have Variable)

5. Not that important, but anyway: maybe add DisplayAspectRatio tag value (as Composite from 1920x1080=16:9).

That's it. I wouldn't bother you with above, but since you decided to support MKV as well... 

Greetings,
Bogdan

[Phil Harvey]

Hi Bogdan,

1. Exiftool lists Chapter data inside "common" Matroska section. Usually, Chapters are listed/viewed as separate section (usually named Chapters or Menu) -which I find better.

I can do this.  Could you send me a sample MKV which contains chapters?  I don't have one of these for testing.

2. ChapterTimeStart hour value is wrong in all cases except if it's complete value is zero. For example
RealValue Displayed

Thanks.  I can fix this too if I have a sample for testing.

3. For TrackType "Video":
-it would be very usefull, if some other important data would be shown.. at least:
e.g.Name = e.g.Value

Code Select Expand

FormatProfile=High@L4.1
FormatReFrames=4 frames
BitRate=8171 kbps
Duration=02:41:00 (must be here in case more video tracks are inside MKV)
I don't know, how to decode those values (seen in some other tools), but they are of great value.
Btw. I suggest displaying VideoFrameRate value on up to three decimal points (23,976 instead of 23,98) -it is important.

4. For TrackType"Audio":
-it would be usefull, if following important data would be shown:

Code Select Expand

Duration=02:41:00 (in case MKV contains several audio tracks)
BitRate=640 kbps
BitRate=Constant (because MP3 can have Variable)

I'll see what I can do. Currently I am not parsing the audio/video streams, and really don't want to do this because to add full support for these would require writing an awful lot of codecs myself.

5. Not that important, but anyway: maybe add DisplayAspectRatio tag value (as Composite from 1920x1080=16:9).

I'll think about this.

Thanks for your feedback.

- Phil

P.S.  Did you try the -U option?  It extracts all available Matroska information except for the audio/video streams themselves.

[BogdanH]

Hi,

I just sent you an mkv example (~25sec =~12Mb) containing chapters.

Of course I don't push on you to implement suggestions I've made. For me, Exiftool is photo tool -that's more than enough.

Greetings,
Bogdan

[Phil Harvey]

Thanks for the sample.  I appreciate the suggestions, they are very useful.

Here is the exiftool output after making a few improvements:

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> exiftool -g1 Sample.mkv
---- ExifTool ----
ExifTool Version Number         : 8.22
---- System ----
File Name                       : Sample.mkv
Directory                       : .
File Size                       : 12 MB
File Modification Date/Time     : 2010:06:04 07:12:25-04:00
File Permissions                : rw-r--r--
---- File ----
File Type                       : MKV
MIME Type                       : video/x-matroska
---- Matroska ----
Doc Type                        : matroska
Doc Type Version                : 2
Doc Type Read Version           : 2
Timecode Scale                  : 1 ms
Muxing App                      : libebml v0.8.0 + libmatroska v0.9.0
Writing App                     : mkvmerge v3.3.0 ('Language') built on Mar 24 2010 14:59:24
Duration                        : 2:35:13
Date/Time Original              : 2010:06:03 18:48:09Z
---- Track1 ----
Track Number                    : 1
Track Type                      : Video
Track Used                      : Yes
Track Default                   : Yes
Track Forced                    : No
Track Timecode Scale            : 1
Video Codec ID                  : V_MPEG4/ISO/AVC
Codec Decode All                : Yes
Video Frame Rate                : 23.976
Track Language                  : eng
Track Name                      : Avatar video
Image Width                     : 1920
Image Height                    : 1080
Video Scan Type                 : Progressive
Display Width                   : 1920
Display Height                  : 1080
---- Track2 ----
Track Number                    : 2
Track Type                      : Audio
Track Used                      : Yes
Track Default                   : Yes
Track Forced                    : No
Track Timecode Scale            : 1
Audio Codec ID                  : A_AC3
Codec Decode All                : Yes
Default Duration                : 32 ms
Track Language                  : eng
Track Name                      : Avatar audio
Audio Sample Rate               : 48000
Audio Channels                  : 6
---- Track3 ----
Track Number                    : 3
Track Type                      : Subtitle
Track Used                      : Yes
Track Default                   : Yes
Track Forced                    : No
Track Timecode Scale            : 1
Codec ID                        : S_TEXT/UTF8
Codec Decode All                : Yes
Track Language                  : slv
Track Name                      : Avatar subtitles
---- Chapter1 ----
Chapter Time Start              : 0 s
Chapter String                  : Intro
Chapter Language                : eng
---- Chapter2 ----
Chapter Time Start              : 20:00
Chapter String                  : 0h 20min
Chapter Language                : eng
---- Chapter3 ----
Chapter Time Start              : 40:00
Chapter String                  : 0h 40min
Chapter Language                : eng
---- Chapter4 ----
Chapter Time Start              : 1:00:00
Chapter String                  : 1h 00min
Chapter Language                : eng
---- Chapter5 ----
Chapter Time Start              : 1:20:00
Chapter String                  : 1h 20min
Chapter Language                : eng
---- Chapter6 ----
Chapter Time Start              : 1:40:00
Chapter String                  : 1h 40min
Chapter Language                : eng
---- Chapter7 ----
Chapter Time Start              : 2:00:00
Chapter String                  : 2h 00min
Chapter Language                : eng
---- Chapter8 ----
Chapter Time Start              : 2:20:00
Chapter String                  : 2h 20min
Chapter Language                : eng
---- Composite ----
Base Name                       : Sample
File Extension                  : mkv
File Type Description           : Matroska Video
Image Size                      : 1920x1080


Here I have implemented your points number 1 and 2.  I didn't find any more useful details in the Matroska metadata and I don't want to parse the audio/video streams, so I couldn't do anything about points 3 or 4.   Also, I didn't implement point 5 because there are complications for calculating the aspect ratio of videos with non-square pixels.  I could probably do this for Matroska only, but if I do this I would want it to apply to all video formats.  And unfortunately calculating this reliably across all formats isn't easy.

- Phil

[BogdanH]

I find this "chapters" output much more readable (and accurate ).

Otherwise I agree with you: at this point Exiftool shows general content of MKV (without going much into details), which should be enough for "info about" use.

Bogdan