diff --git a/youtube_dl/downloader/external.py b/youtube_dl/downloader/external.py
index c31f8910a..61aefd8d4 100644
--- a/youtube_dl/downloader/external.py
+++ b/youtube_dl/downloader/external.py
@@ -243,6 +243,19 @@ class FFmpegFD(ExternalFD):
             # https://github.com/ytdl-org/youtube-dl/issues/11800#issuecomment-275037127
             # http://trac.ffmpeg.org/ticket/6125#comment:10
             args += ['-seekable', '1' if seekable else '0']
+        http_seekable = info_dict.get('_http_seekable')
+        if http_seekable is not None:
+            # setting -http_seekable prevents ffmpeg from guessing if the server
+            # supports seeking in other kinds of requests (by adding the same header
+            # as above: `Range: bytes=0-`)
+            args += ['-http_seekable', '1' if http_seekable else '0']
+        icy = info_dict.get('_icy')
+        if icy is not None:
+            # setting -icy 0 prevents ffmpeg from sending the header `Icy-Metadata: 1`,
+            # which can cause also problems
+            # https://github.com/ytdl-org/youtube-dl/pull/29688
+            # https://trac.ffmpeg.org/ticket/5460#comment:5
+            args += ['-icy', '1' if icy else '0']
 
         args += self._configuration_args()
 
diff --git a/youtube_dl/extractor/nbc.py b/youtube_dl/extractor/nbc.py
index 7cfc030a1..46b44a9be 100644
--- a/youtube_dl/extractor/nbc.py
+++ b/youtube_dl/extractor/nbc.py
@@ -542,6 +542,10 @@ class NBCOlympicsStreamIE(AdobePassIE):
         )['akamai'][0]['tokenizedUrl']
 
         formats = self._extract_m3u8_formats(tokenized_url, pid, 'mp4')
+        for f in formats:
+            f['_seekable'] = False
+            f['_http_seekable'] = False
+            f['_icy'] = False
         self._sort_formats(formats)
 
         return {