[downloader/mhtml] Fix fragments with absolute urls (#3044)

Authored-by: coletdjnz

yt_dlp/downloader/mhtml.py

@@ -166,7 +166,11 @@ body > figure > img {
             if (i + 1) <= ctx['fragment_index']:
                 continue
 
+            fragment_url = fragment.get('url')
+            if not fragment_url:
+                assert fragment_base_url
                 fragment_url = urljoin(fragment_base_url, fragment['path'])
+
             success, frag_content = self._download_fragment(ctx, fragment_url, info_dict)
             if not success:
                 continue

yt_dlp/extractor/francetv.py

@@ -187,7 +187,7 @@ class FranceTVIE(InfoExtractor):
                 'protocol': 'mhtml',
                 'url': 'about:invalid',
                 'fragments': [{
-                    'path': sheet,
+                    'url': sheet,
                     # XXX: not entirely accurate; each spritesheet seems to be
                     # a 10×10 grid of thumbnails corresponding to approximately
                     # 2 seconds of the video; the last spritesheet may be shorter

yt_dlp/extractor/youtube.py

@@ -3208,7 +3208,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                 'width': width,
                 'height': height,
                 'fragments': [{
-                    'path': url.replace('$M', str(j)),
+                    'url': url.replace('$M', str(j)),
                     'duration': min(fragment_duration, duration - (j * fragment_duration)),
                 } for j in range(math.ceil(fragment_count))],
             }