1 files changed, 62 insertions, 0 deletions
diff --git a/yt_dlp/downloader/dash.py b/yt_dlp/downloader/dash.py
new file mode 100644
index 000000000..6444ad692
--- /dev/null
+++ b/yt_dlp/downloader/dash.py
@@ -0,0 +1,62 @@
+from __future__ import unicode_literals
+
+from ..downloader import get_suitable_downloader
+from .fragment import FragmentFD
+
+from ..utils import urljoin
+
+
+class DashSegmentsFD(FragmentFD):
+    """
+    Download segments in a DASH manifest. External downloaders can take over
+    the fragment downloads by supporting the 'dash_frag_urls' protocol
+    """
+
+    FD_NAME = 'dashsegments'
+
+    def real_download(self, filename, info_dict):
+        if info_dict.get('is_live'):
+            self.report_error('Live DASH videos are not supported')
+
+        fragment_base_url = info_dict.get('fragment_base_url')
+        fragments = info_dict['fragments'][:1] if self.params.get(
+            'test', False) else info_dict['fragments']
+
+        real_downloader = get_suitable_downloader(
+            info_dict, self.params, None, protocol='dash_frag_urls', to_stdout=(filename == '-'))
+
+        ctx = {
+            'filename': filename,
+            'total_frags': len(fragments),
+        }
+
+        if real_downloader:
+            self._prepare_external_frag_download(ctx)
+        else:
+            self._prepare_and_start_frag_download(ctx, info_dict)
+
+        fragments_to_download = []
+        frag_index = 0
+        for i, fragment in enumerate(fragments):
+            frag_index += 1
+            if frag_index <= 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'])
+
+            fragments_to_download.append({
+                'frag_index': frag_index,
+                'index': i,
+                'url': fragment_url,
+            })
+
+        if real_downloader:
+            self.to_screen(
+                '[%s] Fragment downloads will be delegated to %s' % (self.FD_NAME, real_downloader.get_basename()))
+            info_dict['fragments'] = fragments_to_download
+            fd = real_downloader(self.ydl, self.params)
+            return fd.real_download(filename, info_dict)
+
+        return self.download_and_append_fragments(ctx, fragments_to_download, info_dict)