Suggestion for new method AudioThumbnail::setReader (w/code)

General JUCE discussion
1

Short story - I want thumbnails for my CD tracks but juce::AudioThumbnail only accepts InputSources.

This is a pity, as that InputSource is only used to create an AudioFormatReader, and I can easily make an AudioCDReader, which is an AudioFormatReader.

I could imagine that anyone wanting to do CD thumbnails would have this issue - or someone wanting to do thumbnails of any other non-standard representation, e.g. URLs.

I was able to easily solve this issue by adding a single method to juce::AudioThumbnail, void setReader (AudioFormatReader* reader, int64 hashCode);This works fine on my development system, at least, and I don’t see any reason why it would not work in general.

The full code is here: void AudioThumbnail::setReader (AudioFormatReader* reader_, int64 hashCode) { if (! (cache.loadThumb (*this, hashCode) && isFullyLoaded())) { { const ScopedLock sl (readerLock); reader = reader_; } if (reader != 0) { initialiseFromAudioFile (*reader); cache.addThumbnail (this); } } }

2

Seems like a good request. I’m just in the middle of tarting-up the thumbnail stuff, so I’ll see what I can do…

3

These days we talk about “easy virtueing up” the code to avoid possible accusations of gender bias. :wink:

4

:lol:

5

Jules, the new methods for the AudioThumbnail are great!
But looks like calling
AudioThumbnail::isFullyLoaded()
returns always false now.

6

Ah yes, thanks, I’ll get that sorted out!

7

Fast work, Jules.

I dropped it in in place of my hacked code and it not only worked, it didn’t have a bug my code did. :smiley: Instant thumbnails for CD tracks!

I’m discovering more about CDs and will report in a separate thread.

8

Jules,
what about adding a method to AudioThumbnailCache that would let save and load the whole content of it to a file?
I know there are already AudioThumbnailCache::storeThumb and AudioThumbnailCache::loadThumb,
but I’d like to be able to load the content before creating the thumbnails.

9

Well you can already do that - just create a thumbnail, load it, and add it to the cache.

10

Sorry to revive this old thread, but recently I added a couple of functions to the AudioThumbnailCache to do what I needed.
They are something like:

[code]void AudioThumbnailCache::storeCache(File& file)
{
FileOutputStream* mo = file.createOutputStream();

for (int i = thumbs.size(); --i >= 0;)
{
	mo->writeInt64(thumbs[i]->data.getSize());
	mo->write(thumbs[i]->data.getData(), thumbs[i]->data.getSize());
	mo->writeInt64(thumbs[i]->hash);
}

delete mo;

}

void AudioThumbnailCache::loadCache(File& file)
{
FileInputStream* mi = file.createInputStream();

while(mi->getPosition() < mi->getTotalLength())
{
	ThumbnailCacheEntry* te = new ThumbnailCacheEntry();
	
	int64 size = mi->readInt64();
	te->data.setSize(size);
	mi->read(te->data.getData(), (int)size); 
  te->hash = mi->readInt64();
	
	thumbs.add(te);
}

delete mi;

}[/code]

These let me store and load the whole cache to/from a file, BEFORE creating the thumbnails. In this way, when the thumbnails get re-created (and they use AudioThumbnail::setReader), the waveforms are immediately fully loaded.
I don’t know if you like the idea, but could this be an addition to the AudioThumbnailCache class?

11

ScopedPointers, please!! And check your pointers for nullness!

…but aside from that, thanks, not a bad idea! Can’t look at it right now, but remind me again if I forget.

12

Yeah! I usually use scoped pointers, but this code was just an idea…
Thank you!

13

Bump :stuck_out_tongue: