Support .txt files as a line-by-line media list rather than streams (#10059)

* Update streams.txt default

Signed-off-by: Colin Wong <cwongmath@gmail.com>

* Change streams list extension to .streams

* Read txt as media per line

* Missed one

* Missed another one

* Update dataloaders.py

* Update detect.py

* Update dataloaders.py

* Update detect.py

* Update predict.py

* Update predict.py

* Update README.md

Signed-off-by: Colin Wong <cwongmath@gmail.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

classify/predict.py

@@ -8,6 +8,8 @@ Usage - sources:
                                                                    vid.mp4                         # video
                                                                    screen                          # screenshot
                                                                    path/                           # directory
+                                                                   list.txt                        # list of images
+                                                                   list.streams                    # list of streams
                                                                    'path/*.jpg'                    # glob
                                                                    'https://youtu.be/Zgi9g1ksQHc'  # YouTube
                                                                    'rtsp://example.com/media.mp4'  # RTSP, RTMP, HTTP stream
@@ -74,7 +76,7 @@ def run(
     save_img = not nosave and not source.endswith('.txt')  # save inference images
     is_file = Path(source).suffix[1:] in (IMG_FORMATS + VID_FORMATS)
     is_url = source.lower().startswith(('rtsp://', 'rtmp://', 'http://', 'https://'))
-    webcam = source.isnumeric() or source.endswith('.txt') or (is_url and not is_file)
+    webcam = source.isnumeric() or source.endswith('.streams') or (is_url and not is_file)
     screenshot = source.lower().startswith('screen')
     if is_url and is_file:
         source = check_file(source)  # download