--embed-thumbnail crashes the program if the file has the wrong type

[Profpatsch]

• I've verified and I assure that I'm running youtube-dl 2016.08.28

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What is the purpose of your issue?

• Bug report (encountered problems with youtube-dl)

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If the purpose of this issue is a bug report, site support request or you are not completely sure provide the full verbose output as follows:

[info] Writing video description to: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.description
[info] Writing video annotations to: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.annotations.xml
[info] Writing video description metadata as JSON to: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.info.json
[youtube] WrO9PTpuSSs: Downloading thumbnail ...
[youtube] WrO9PTpuSSs: Writing thumbnail to: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.jpg
[download] Destination: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.f247.webm
[download] 100% of 167.34MiB in 11:38
[download] Destination: Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.f251.webm
[download] 100% of 60.15MiB in 04:41
[ffmpeg] Merging formats into "Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.webm"
Deleting original file Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.f247.webm (pass -k to keep)
Deleting original file Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.f251.webm (pass -k to keep)
[ffmpeg] Adding metadata to 'Nujabes - Modal Soul (Full Album)-WrO9PTpuSSs.webm'
[ffmpeg] There aren't any subtitles to embed
ERROR: Only mp3 and m4a/mp4 are supported for thumbnail embedding for now.

Description of your issue, suggested solution and other information

The program crashes with --embed-thumbnails enabled when the file is not mp3/m4a/mp4.
I wanted to backup a long playlist over night, but it crashed after video 9.

Invocation:

youtube-dl --yes-playlist --write-description --write-info-json --write-annotations --write-thumbnail --all-subs --add-metadata --embed-subs --embed-thumbnail <playlist>

I wrote a small, dirty patch that prevents the crash:

diff --git a/youtube_dl/postprocessor/embedthumbnail.py b/youtube_dl/postprocessor/embedthumbnail.py
index 3bad5a2..cfc0e07 100644
--- a/youtube_dl/postprocessor/embedthumbnail.py
+++ b/youtube_dl/postprocessor/embedthumbnail.py
@@ -87,6 +87,8 @@ class EmbedThumbnailPP(FFmpegPostProcessor):
                 os.remove(encodeFilename(filename))
                 os.rename(encodeFilename(temp_filename), encodeFilename(filename))
         else:
-            raise EmbedThumbnailPPError('Only mp3 and m4a/mp4 are supported for thumbnail embedding for now.')
+            # should be correctly caught outside, but the calling system is confusing
+            # raise EmbedThumbnailPPError('Only mp3 and m4a/mp4 are supported for thumbnail embedding for now.')
+            self._downloader.report_warning('Only mp3 and m4a/mp4 are supported for thumbnail embedding for now.')

         return [], info

The nice way would be to catch the exception outside of the class and handle it correctly, but I couldn’t find out where it is called.
It should also be clarified how the semantics should be: does --embed-thumbnail guarantee that a thumbnail exists in the output? can it embed if there is a thumbnail (then the error should not exist)? does it try its best and skip if it doesn’t work?

[Tatsh]

You should make a PR.

--embed-thumbnail can fail for a lot of reasons and it especially does not work on non-YouTube sites. A workaround to skip this being fatal would be fine. Either it simply does by default or there's a new flag: --non-fatal-embed-thumbnail (only this flag and not requiring --embed-thumbnail just to keep things simple).

[Profpatsch]

You should make a PR.

As I said, the code is too confusing for me to make a nice PR that isn’t as hacky as the one above.

[532910]

Is any update there through years? Why this is just ignored, thought the fix is trivial?

I got the same issue trying to use --all-formats --embed-thumbnail

[532910]

look like --ignore-errors solves this issue
youtube-dl --embed-thumbnail --all-formats --ignore-errors downloads all tracks ignoring errors
@Profpatsch, could you confirm and close?

[Tatsh]

Ignoring errors is not a solution

[532910]

any explanation?

[Tatsh]

All your command does is ignore any error. It would ignore errors you may want to catch and stop for. For a single video argument for this issue ignoring the error may be okay, but it's not okay for playlists or multiple video URLs as arguments.

[532910]

This is exactly what I want for playlists.--ignore-errors
Moreover, there are other errors (geo restriction for example) that crash and are mitigated with --ignore-errors.
I believe each error should have a personal switch, like --ignore-errors=all --ignore-errors=thumbnail --ignore-errors=geo,thumbnail --ignore-errors=all,-geo, a new issue should be opened and this one be closed.