Tracs validation added. A warning is thrown if the input contains a video strem, but the requested output format doesn't support it

web/backend/api/formats.py

@@ -0,0 +1,25 @@
+"""Endpoint to expose format information to the frontend."""
+
+from fastapi import APIRouter
+
+from backend.constants import FORMAT_INFO
+
+router = APIRouter(prefix="/api", tags=["formats"])
+
+
+@router.get("/formats")
+async def get_formats():
+    """
+    Return the list of supported container formats with their properties.
+    """
+    return {
+        "formats": [
+            {
+                "name": name,
+                "ffmpeg": info["ffmpeg"],
+                "extension": info["ext"],
+                "audio_only": info["audio_only"],
+            }
+            for name, info in FORMAT_INFO.items()
+        ]
+    }

web/backend/api/info.py

@@ -0,0 +1,35 @@
+"""Endpoint to retrieve stream information for an uploaded file."""
+
+from fastapi import APIRouter, HTTPException
+
+from backend.config import settings
+from backend.services.file_manager import FileManager
+from backend.services.task_manager import task_manager
+from backend.ffmpeg import get_stream_info
+
+router = APIRouter(prefix="/api", tags=["info"])
+
+
+@router.get("/info/{task_id}")
+async def get_task_info(task_id: str):
+    """
+    Return stream information (has_audio, has_video, has_subtitle) for the uploaded file.
+    """
+    if not task_manager.has_task(task_id):
+        raise HTTPException(status_code=404, detail=f"Task {task_id} not found")
+
+    input_path = FileManager.get_input_path(task_id)
+    if not input_path or not input_path.exists():
+        raise HTTPException(status_code=404, detail="Input file not found")
+
+    try:
+        info = get_stream_info(str(input_path))
+        return {
+            "task_id": task_id,
+            "has_audio": info["has_audio"],
+            "has_video": info["has_video"],
+            "has_subtitle": info["has_subtitle"],
+            "audio_codec": info["audio_codec"],
+        }
+    except Exception as e:
+        raise HTTPException(status_code=500, detail=f"Failed to retrieve stream info: {str(e)}")

web/backend/constants.py

@@ -0,0 +1,12 @@
+FORMAT_INFO = {
+    'mp3':      {'ffmpeg': 'mp3',      'ext': '.mp3',  'audio_only': True},
+    'm4a':      {'ffmpeg': 'mp4',      'ext': '.m4a',  'audio_only': True},
+    'mp4':      {'ffmpeg': 'mp4',      'ext': '.mp4',  'audio_only': False},
+    'mkv':      {'ffmpeg': 'matroska', 'ext': '.mkv',  'audio_only': False},
+    'matroska': {'ffmpeg': 'matroska', 'ext': '.mkv',  'audio_only': False},
+    'ogg':      {'ffmpeg': 'ogg',      'ext': '.ogg',  'audio_only': True},
+    'opus':     {'ffmpeg': 'ogg',      'ext': '.opus', 'audio_only': True},
+    'flac':     {'ffmpeg': 'flac',     'ext': '.flac', 'audio_only': True},
+    'wav':      {'ffmpeg': 'wav',      'ext': '.wav',  'audio_only': True},
+    'aac':      {'ffmpeg': 'adts',     'ext': '.aac',  'audio_only': True},
+}

web/backend/ffmpeg.py

@@ -0,0 +1,79 @@
+"""FFmpeg/FFprobe interaction utilities for the web backend."""
+
+import subprocess
+import json
+
+
+def get_stream_info(input_file: str):
+    """
+    Retrieve stream information (audio, video, subtitle presence) from a media file.
+    Returns a dict with keys: has_audio, has_video, has_subtitle, audio_codec.
+    """
+    # Get audio codec (if any)
+    audio_codec = None
+    try:
+        cmd = [
+            'ffprobe', '-v', 'error',
+            '-select_streams', 'a:0',
+            '-show_entries', 'stream=codec_name',
+            '-of', 'default=noprint_wrappers=1:nokey=1',
+            input_file
+        ]
+        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
+        codec = result.stdout.strip().lower()
+        if codec:
+            audio_codec = codec
+    except Exception:
+        pass
+
+    # Check for video stream
+    has_video = False
+    try:
+        cmd = [
+            'ffprobe', '-v', 'error',
+            '-select_streams', 'v',
+            '-show_entries', 'stream=codec_type',
+            '-of', 'default=noprint_wrappers=1:nokey=1',
+            input_file
+        ]
+        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
+        has_video = bool(result.stdout.strip())
+    except Exception:
+        pass
+
+    # Check for subtitle stream
+    has_subtitle = False
+    try:
+        cmd = [
+            'ffprobe', '-v', 'error',
+            '-select_streams', 's',
+            '-show_entries', 'stream=codec_type',
+            '-of', 'default=noprint_wrappers=1:nokey=1',
+            input_file
+        ]
+        result = subprocess.run(cmd, capture_output=True, text=True, check=False)
+        has_subtitle = bool(result.stdout.strip())
+    except Exception:
+        pass
+
+    return {
+        'has_audio': audio_codec is not None,
+        'has_video': has_video,
+        'has_subtitle': has_subtitle,
+        'audio_codec': audio_codec,
+    }
+
+
+def get_audio_duration(input_file: str) -> float:
+    """Get the duration of the audio file in seconds."""
+    cmd = [
+        'ffprobe', '-v', 'error',
+        '-show_entries', 'format=duration',
+        '-of', 'default=noprint_wrappers=1:nokey=1',
+        input_file
+    ]
+    result = subprocess.run(cmd, capture_output=True, text=True, check=False)
+    try:
+        return float(result.stdout.strip())
+    except ValueError:
+        return 0.0

web/backend/main.py

@@ -5,8 +5,7 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from backend.config import settings
-from backend.api import upload, split, status, download
-from backend.api.websocket import router as websocket_router
+from backend.api import upload, split, status, download, websocket, formats, info
 from backend.services import progress_publisher
 
 app = FastAPI(
@@ -36,7 +35,9 @@ app.include_router(upload.router)
 app.include_router(split.router)
 app.include_router(status.router)
 app.include_router(download.router)
-app.include_router(websocket_router)
+app.include_router(websocket.router)
+app.include_router(formats.router)   # new
+app.include_router(info.router)      # new
 
 
 @app.get("/")