Series and title misinterpreted when program doesn't have a title specified in Areena

[maxminstr]

It seems that yle-dl misinterprets ${series} and ${title} variables when audio program episode doesn't have a title specified in Areena.

In these instances yle-dl interprets series as title, and leaves ${series} variable empty.

Here is an example using audio program series called Iltasoitto:

https://areena.yle.fi/podcastit/1-63391641

• This episode has both series and title specified in Areena, from yle-dl metadata: "title": "Iltasoitto: Iltasoitto Kuningatar Elisabet II:n muistoksi: 2022-09-08T22:15",
• This works correctly in yle-dl.

https://areena.yle.fi/podcastit/1-63135148

• This episode has only series specified in Areena, from yle-dl metadata: "title": "Iltasoitto: 2022-09-09T22:20",
• Such episodes with no title appear with a default title in Areena, in this case "pe 9.9.2022".
• This episode doesn't work correctly in yle-dl: series variable is left empty, and series name instead appears in title variable.

As series variable is empty, output templates don't work correctly (I've included full command):

yle-dl https://areena.yle.fi/podcastit/1-63135148 --vfat --create-dirs --no-overwrite --output-template "YLE Radio 1 - ${series}/${timestamp} - YLE Radio 1 - ${series} - ${title} - ${program_id}"

In Windows this results to a failed download:

Output file: YLE Radio 1 - \2022-09-09T22_20 - YLE Radio 1 - - Iltasoitto - 1-63135148.mp3
file:YLE Radio 1 - \2022-09-09T22_20 - YLE Radio 1 - - Iltasoitto - 1-63135148.mp3: No such file or directory

In Linux the file gets saved but it has practically no name at all ("Yle Radio 1 -/- YLE Radio 1 - - -.mp3".

My suggestions:

1. Please interpret series and title correctly where there is no title in Areena. Maybe use a default title like Areena, ie. date?

2. Please consider adding a placeholder value for unavailable metadata fields: Even if this missing variable issue is resolved, it is possible that in other scenarios a variable might end up empty. Youtube-dl uses "NA" as a default value for such instances (it can be changed using flag --output-na-placeholder). This would help ensure that output templates don't cause failed downloads.

[aajanki]

The series/episode title detection is currently a bit of a hack. I'll see if I can make it more robust. Some way to optionally specify the placeholder value for unavailable fields also sound like a good idea.

[aajanki]

I have implemented --output-na-placeholder NA option for setting a replacement value for missing metadata fields. The default is still to replace missing fields with an empty string.

I also modified the title detection. Now the series title should get set correctly and date is used as the episode title like in Areena.

Note that you should use single quotes for the output template at least on Linux. Otherwise $foo gets interpreted as a shell variable and that messes up the template.

After the changes this command will download a a file YLE Radio 1 - Iltasoitto/2022-09-09T22_20 - YLE Radio 1 - Iltasoitto - pe 9.9.2022 - 1-63135148.mp3:

yle-dl https://areena.yle.fi/podcastit/1-63135148 --vfat --create-dirs --no-overwrite --output-template 'YLE Radio 1 - ${series}/${timestamp} - YLE Radio 1 - ${series} - ${title} - ${program_id}' --output-na-placeholder NA