experimental[minor]: Create Closed Captioning Chain for .mp4 videos (#14059)

Description: Video imagery to text (Closed Captioning)
This pull request introduces the VideoCaptioningChain, a tool for
automated video captioning. It processes audio and video to generate
subtitles and closed captions, merging them into a single SRT output.

Issue: https://github.com/langchain-ai/langchain/issues/11770
Dependencies: opencv-python, ffmpeg-python, assemblyai, transformers,
pillow, torch, openai
Tag maintainer:
@baskaryan
@hwchase17


Hello!

We are a group of students from the University of Toronto
(@LunarECL, @TomSadan, @nicoledroi1, @A2113S) that want to make a
contribution to the LangChain community! We have ran make format, make
lint and make test locally before submitting the PR. To our knowledge,
our changes do not introduce any new errors.

Thank you for taking the time to review our PR!

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/experimental/tests/integration_tests/test_video_captioning.py

@@ -0,0 +1,28 @@
+"""Integration test for video captioning."""
+from langchain_openai import ChatOpenAI
+
+from langchain_experimental.video_captioning.base import VideoCaptioningChain
+
+
+def test_video_captioning_hard() -> None:
+    """Test input that is considered hard for this chain to process."""
+    URL = """
+    https://ia904700.us.archive.org/22/items/any-chibes/X2Download.com
+    -FXX%20USA%20%C2%ABPromo%20Noon%20-%204A%20Every%20Day%EF%BF%BD%EF
+    %BF%BD%C2%BB%20November%202021%EF%BF%BD%EF%BF%BD-%281080p60%29.mp4
+    """
+    chain = VideoCaptioningChain(
+        llm=ChatOpenAI(
+            model="gpt-4",
+            max_tokens=4000,
+        )
+    )
+    srt_content = chain.run(video_file_path=URL)
+
+    assert (
+        "mustache" in srt_content
+        and "Any chives?" in srt_content
+        and "How easy? A little tighter." in srt_content
+        and "it's a little tight in" in srt_content
+        and "every day" in srt_content
+    )