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| author | Sergey M․ <dstftw@gmail.com> | 2016-02-27 07:01:11 +0600 |
|---|---|---|
| committer | Sergey M․ <dstftw@gmail.com> | 2016-02-27 07:01:11 +0600 |
| commit | 9cdffeeb3fbfa28407a8a519a58b3714b7cec874 (patch) | |
| tree | 5b71ae4e649453796921629aaed8de602fb958fb | |
| parent | fbb6edd298a34cf63a5fd0bd900ca2337038810c (diff) | |
| download | youtube-dl-9cdffeeb3fbfa28407a8a519a58b3714b7cec874.tar.xz | |
[extractor/common] Clarify rationale on media playlist detection
| -rw-r--r-- | youtube_dl/extractor/common.py | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py index 51351fb57..3f16b1b9e 100644 --- a/youtube_dl/extractor/common.py +++ b/youtube_dl/extractor/common.py @@ -1033,11 +1033,21 @@ class InfoExtractor(object): return [] m3u8_doc, urlh = res m3u8_url = urlh.geturl() - # A Media Playlist Tag MUST NOT appear in a Master Playlist - # https://tools.ietf.org/html/draft-pantos-http-live-streaming-17#section-4.3.3 - # The EXT-X-TARGETDURATION tag is REQUIRED for every M3U8 Media Playlists - # https://tools.ietf.org/html/draft-pantos-http-live-streaming-17#section-4.3.3.1 - if '#EXT-X-TARGETDURATION' in m3u8_doc: + + # We should try extracting formats only from master playlists [1], i.e. + # playlists that describe available qualities. On the other hand media + # playlists [2] should be returned as is since they contain just the media + # without qualities renditions. + # Fortunately, master playlist can be easily distinguished from media + # playlist based on particular tags availability. As of [1, 2] master + # playlist tags MUST NOT appear in a media playist and vice versa. + # As of [3] #EXT-X-TARGETDURATION tag is REQUIRED for every media playlist + # and MUST NOT appear in master playlist thus we can clearly detect media + # playlist with this criterion. + # 1. https://tools.ietf.org/html/draft-pantos-http-live-streaming-17#section-4.3.4 + # 2. https://tools.ietf.org/html/draft-pantos-http-live-streaming-17#section-4.3.3 + # 3. https://tools.ietf.org/html/draft-pantos-http-live-streaming-17#section-4.3.3.1 + if '#EXT-X-TARGETDURATION' in m3u8_doc: # media playlist, return as is return [{ 'url': m3u8_url, 'format_id': m3u8_id, |