Welcome Guest 

Show/Hide Header

Welcome Guest, posting in this forum requires registration.





Pages: 1 [2]
Author Topic: Save modified tags to video file
2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 12:15
Quote

The only possibility I can think of is that the files do not have the udta-meta-ilst sequence of atoms. If any of these are missing Yate always rewrites the file. This would only happen once. When writing in place Yate is essentially rewriting the ilst atom, adjusting the free space, etc.

I can look at this...but before I go down the rabbit hole please have a look at one of your files before tagging it. Do a View>Raw Data. Once the Log Viewer opens do a search for udta. Then look at the subtree to see if meta is missing.

If you wish you can save the file and send it to us at support@2manyrobots.com.

2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 12:37
Quote

When you have a look at the raw log ... before tagging in Yate, please send the file saved file regardless. Fixing the missing components in-place is still not possible if there is no free space where appropriate.

UKenGB
Newbie
Posts: 19
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 13:05
Quote

Email sent

UKenGB
Newbie
Posts: 19
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 13:06
Quote

Do you want me to send a 2 GB MP4 file by email?

UKenGB
Newbie
Posts: 19
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 13:29
Quote

You are adding this to the file when saving:-

User Defined Text Info:
	desc = iTunMOVI
	value = <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict/>
</plist>

That is increasing the required space and causing it to rewrite the whole file. Subler doesn't add anything.

I'll email the 'metadata as text' for each version so you can see.

2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 13:30
Quote

Hold on 🙂 I'll give you a breakdown in a few minutes.

2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 14:06
Quote

Here's the analysis of the before and after raw dumps which were sent:

First off both files are well formed and are not missing any of the udta-meta-ilst atoms.

The first file (before Yate) has 0 free bytes. Adding even 1 byte will cause the file to be rewritten. The second file has 2048 bytes of free space which is the Yate default and is what I would expect after writing the entire file.

The issue is that Yate writes more metadata than the other application. This is common for all audio file types. There is no way I can add in per field granularity for every field and every tagger tends to write a different set of metadata. In this case the additional items are not empty. (Empty items are not written).

Here's the detailed breakdown discussed primarily from the Yate edited file.

76 bytes were added for the Media type.
25 byte were added for the Content Advisory
24 bytes were added for the Show Description
The Show Name decreased in size by 10 bytes
72 bytes were added for the video classification.
233 bytes were added for iTunMOVI. (This can be disabled in Preferences-Audio-MPEG-4-Process iTunMOVI for files with video)

The net difference is that 440 bytes were added.

The other application more than likely does not rewrite the file as you have reduced the size of the Show Name field by 10 bytes. In Yate this is negated by the other added metadata.

There is no way to look at this situation as 'I only want what's in the other application'. The added metadata may not be useful to you but it is used by many others. Also, as I said already said I cannot build in per field exclusion.

I understand your angst but 440 bytes in a video file is insignificant. Not having any free space in a video file is somewhat insane. v6 of Yate will allow different free space allotments for audio and video files.

2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 20, 2020, 22:54
Quote

I've had a look at Subler. The application is lightning fast on saves. The reason is that the metadata area, when at the beginning of the file is marked as free and relocated to the end of the file. In the dump I was sent this resulted in the file size being increased by 3.5mb for a 10 byte change in the metadata.

If anyone has an opinion on this approach, please let us know.

2MR2
Administrator
Posts: 1313
Permalink
Post Re: Save modified tags to video file
on: June 21, 2020, 13:13
Quote

If you are using Subler please read this.

In MPEG-4 files it is permitted that the last atom at the root level in the file can have a length of 0. It means 'extends to the end of file'. In playing around with the application I had three files destroyed. The three destroyed files all had a small free atom with a size of 0 at the end. Subler does not change the 0 size to a non zero value when appending the moov block that it relocates to the end of the file. This results in a destroyed file. There is no way to fix the files as everything from the old 0 size free atom now looks like a big free block. The files are missing the moov atom and cannot be played.

I would let the developer know about this but I cannot find any way of contacting him.

Pages: 1 [2]
Mingle Forum by cartpauj
Version: 1.0.34 ; Page loaded in: 0.077 seconds.