device

app.py

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+from collections import deque
+
+import streamlit as st
+import torch
+from streamlit_player import st_player
+from transformers import AutoModelForCTC, Wav2Vec2Processor
+
+from streaming import ffmpeg_stream
+
+device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
+player_options = {
+    "events": ["onProgress"],
+    "progress_interval": 200,
+    "volume": 1.0,
+    "playing": True,
+    "loop": False,
+    "controls": False,
+    "muted": False,
+    "config": {"youtube": {"playerVars": {"start": 1}}},
+}
+
+
+@st.cache(hash_funcs={torch.nn.parameter.Parameter: lambda _: None})
+def load_model(model_path="facebook/wav2vec2-large-robust-ft-swbd-300h"):
+    processor = Wav2Vec2Processor.from_pretrained(model_path)
+    model = AutoModelForCTC.from_pretrained(model_path).to(device)
+    return processor, model
+
+
+processor, model = load_model()
+
+
+def stream_text(url, chunk_duration_ms, pad_duration_ms):
+    sampling_rate = processor.feature_extractor.sampling_rate
+
+    # calculate the length of logits to cut from the sides of the output to account for input padding
+    output_pad_len = model._get_feat_extract_output_lengths(int(sampling_rate * pad_duration_ms / 1000))
+
+    # define the audio chunk generator
+    stream = ffmpeg_stream(url, sampling_rate, chunk_duration_ms=chunk_duration_ms, pad_duration_ms=pad_duration_ms)
+
+    leftover_text = ""
+    for i, chunk in enumerate(stream):
+        input_values = processor(chunk, sampling_rate=sampling_rate, return_tensors="pt").input_values
+
+        with torch.no_grad():
+            logits = model(input_values.to(device)).logits[0]
+            if i > 0:
+                logits = logits[output_pad_len : len(logits) - output_pad_len]
+            else:  # don't count padding at the start of the clip
+                logits = logits[: len(logits) - output_pad_len]
+
+            predicted_ids = torch.argmax(logits, dim=-1).cpu().tolist()
+            if processor.decode(predicted_ids).strip():
+                leftover_ids = processor.tokenizer.encode(leftover_text)
+                # concat the last word (or its part) from the last frame with the current text
+                text = processor.decode(leftover_ids + predicted_ids)
+                # don't return the last word in case it's just partially recognized
+                text, leftover_text = text.rsplit(" ", 1)
+                yield text
+            else:
+                yield leftover_text
+                leftover_text = ""
+
+    yield leftover_text
+
+
+def main():
+    state = st.session_state
+    st.header("YouTube Streaming ASR with Robust Wav2Vec2")
+
+    with st.form(key="inputs_form"):
+        state.youtube_url = st.text_input("YouTube URL", "https://www.youtube.com/watch?v=yJmiZ1Mo1cQ")
+        state.chunk_duration_ms = st.slider("Audio chunk duration (ms)", 2000, 10000, 3000, 100)
+        state.pad_duration_ms = st.slider("Padding duration (ms)", 100, 5000, 1000, 100)
+        submit_button = st.form_submit_button(label="Submit")
+
+    if submit_button or "asr_stream" not in state:
+        # a hack to update the video player on value changes
+        state.youtube_url = (
+            state.youtube_url.split("&hash=")[0]
+            + f"&hash={state.chunk_duration_ms}-{state.pad_duration_ms}"
+        )
+        state.asr_stream = stream_text(
+            state.youtube_url, state.chunk_duration_ms, state.pad_duration_ms
+        )
+        state.chunks_taken = 0
+        state.lines = deque([], maxlen=3)  # limit to the last 3 lines of subs
+
+    player = st_player(state.youtube_url, **player_options, key="youtube_player")
+
+    if "asr_stream" in state and player.data and player.data["played"] < 1.0:
+        # check how many seconds were played, and if more than processed - write the next text chunk
+        processed_seconds = state.chunks_taken * (state.chunk_duration_ms / 1000)
+        if processed_seconds < player.data["playedSeconds"]:
+            text = next(state.asr_stream)
+            state.lines.append(text)
+            state.chunks_taken += 1
+    if "lines" in state:
+        # print the last 3 lines of subs
+        st.code("\n".join(state.lines))
+
+
+if __name__ == "__main__":
+    main()