youtube-dl repeats thumbnail embedding if file already exists

[nearcatch]

[download] Downloading video 87 of 87
[youtube] 8K-RKUbS38o: Downloading webpage
[youtube] 8K-RKUbS38o: Downloading video info webpage
[youtube] 8K-RKUbS38o: Extracting video information
[youtube] 8K-RKUbS38o: Downloading DASH manifest
[youtube] 8K-RKUbS38o: Downloading DASH manifest
[youtube] 8K-RKUbS38o: Downloading thumbnail ...
[youtube] 8K-RKUbS38o: Writing thumbnail to: F:\Random\ASMR\accidentallygraceful\20150917 ASMR _ Softly Spoken Stories  Thumbelina (A Bedtime Story For Relaxation & Sleep)_8K-RKUbS38o.jpg
[download] F:\Random\ASMR\accidentallygraceful\20150917 ASMR _ Softly Spoken Stories  Thumbelina (A Bedtime Story For Relaxation & Sleep)_8K-RKUbS38o.mp4 has already been downloaded and merged
[atomicparsley] Adding thumbnail to "F:\Random\ASMR\accidentallygraceful\20150917 ASMR _ Softly Spoken Stories  Thumbelina (A Bedtime Story For Relaxation & Sleep)_8K-RKUbS38o.mp4"

Using latest version (2015-09-22) as of this post. As you can see from the code, the thumbnail is downloaded before youtube-dl checks the video and sees it has already been downloaded. Then the thumbnail logic embeds the thumbnail file since it is there. This results in a video with duplicate thumbnails.

If the video already exists maybe youtube-dl should assume a thumbnail was already embedded and discard the downloaded one.

[jaimeMF]

If the video already exists maybe youtube-dl should assume a thumbnail was already embedded and discard the downloaded one.

It's not that simple, you can quit youtube-dl after the video is downloaded but before the thumbnail is embedded. I guess we should check with ffmpeg if the file already has a thumbnail

[nearcatch]

I am running youtube-dl through a batch file so I don't think I have a way to quit youtube-dl when the file is already downloaded.