audio_splitter/constants.py

@@ -1,7 +1,9 @@
-"""Global constants and default values."""
+# audio_splitter/constants.py
+"""Global constants for the audio splitter."""
 
-# Mapping from user‑friendly format names to FFmpeg format identifiers,
+# ------------------------------------------------------------------------------
-# file extensions, and whether the container is audio‑only.
+# Container information (used for output format selection)
+# ------------------------------------------------------------------------------
 FORMAT_INFO = {
     'mp3':      {'ffmpeg': 'mp3',      'ext': '.mp3',  'audio_only': True},
     'm4a':      {'ffmpeg': 'mp4',      'ext': '.m4a',  'audio_only': True},
@@ -15,6 +17,37 @@ FORMAT_INFO = {
     'aac':      {'ffmpeg': 'adts',     'ext': '.aac',  'audio_only': True},
 }
 
-# Default characters to replace when --replace-bad-chars is enabled.
+# ------------------------------------------------------------------------------
-# Includes common punctuation, single quote, and a trailing space.
+# Container list with display names and extensions (for frontend)
-DEFAULT_BAD_CHARS = r',!@#№$;:%^&?*(){}[]\/<>+=~`\' '
+# ------------------------------------------------------------------------------
+CONTAINER_INFO = [
+    {'name': 'mp3',      'ffmpeg': 'mp3',      'extension': '.mp3',  'audio_only': True},
+    {'name': 'm4a',      'ffmpeg': 'mp4',      'extension': '.m4a',  'audio_only': True},
+    {'name': 'mp4',      'ffmpeg': 'mp4',      'extension': '.mp4',  'audio_only': False},
+    {'name': 'mkv',      'ffmpeg': 'matroska', 'extension': '.mkv',  'audio_only': False},
+    {'name': 'ogg',      'ffmpeg': 'ogg',      'extension': '.ogg',  'audio_only': True},
+    {'name': 'opus',     'ffmpeg': 'ogg',      'extension': '.opus', 'audio_only': True},
+    {'name': 'flac',     'ffmpeg': 'flac',     'extension': '.flac', 'audio_only': True},
+    {'name': 'wav',      'ffmpeg': 'wav',      'extension': '.wav',  'audio_only': True},
+    {'name': 'aac',      'ffmpeg': 'adts',     'extension': '.aac',  'audio_only': True},
+]
+
+# ------------------------------------------------------------------------------
+# Codec information (used for transcoding options)
+# ------------------------------------------------------------------------------
+CODEC_INFO = [
+    # codec name, ffmpeg encoder name, recommended container, supports transcoding
+    {'name': 'mp3',      'ffmpeg': 'libmp3lame', 'recommended_container': 'mp3',  'supports_transcoding': True},
+    {'name': 'aac',      'ffmpeg': 'aac',        'recommended_container': 'm4a',  'supports_transcoding': True},
+    {'name': 'opus',     'ffmpeg': 'libopus',    'recommended_container': 'opus', 'supports_transcoding': True},
+    {'name': 'flac',     'ffmpeg': 'flac',       'recommended_container': 'flac', 'supports_transcoding': True},
+    {'name': 'vorbis',   'ffmpeg': 'libvorbis',  'recommended_container': 'ogg',  'supports_transcoding': True},
+    {'name': 'alac',     'ffmpeg': 'alac',       'recommended_container': 'm4a',  'supports_transcoding': True},
+    {'name': 'pcm_s16le','ffmpeg': 'pcm_s16le',  'recommended_container': 'wav',  'supports_transcoding': True},
+]
+
+# Map codec name → recommended container
+CODEC_TO_CONTAINER_MAP = {codec['name']: codec['recommended_container'] for codec in CODEC_INFO}
+
+# Default bad characters (unchanged)
+DEFAULT_BAD_CHARS = r'!@#№$;:%^&?*(){}[]\/<>+=~`\' '

audio_splitter/formats.py

@@ -1,16 +1,17 @@
+# audio_splitter/formats.py
 """Container format decision and validation."""
 
 from typing import Dict, Optional
 
-from .constants import FORMAT_INFO
+from .constants import FORMAT_INFO, CODEC_TO_CONTAINER_MAP, CONTAINER_INFO
 
 
 def determine_default_format(container: Optional[str], codec: Optional[str]) -> Optional[str]:
     """
     Given the container format and audio codec, determine the recommended output format.
 
-    This is used when the user has not explicitly specified a format.
+    This uses the CODEC_TO_CONTAINER_MAP to map codec → container.
-    It prioritizes the codec to choose the most appropriate container/extension.
+    If the codec is not found, it falls back to the container.
 
     Args:
         container: Container name (e.g., 'ogg', 'mp4', 'matroska') as returned by get_container_format().
@@ -22,37 +23,14 @@ def determine_default_format(container: Optional[str], codec: Optional[str]) ->
     if not container:
         return None
 
-    # Codec-based decisions (highest priority)
+    # Codec-based decision (highest priority)
-    if codec == 'opus':
+    if codec and codec in CODEC_TO_CONTAINER_MAP:
-        return 'opus'
+        return CODEC_TO_CONTAINER_MAP[codec]
-    if codec in ('aac', 'alac', 'he-aac'):
-        return 'm4a'
-    if codec == 'mp3':
-        return 'mp3'
-    if codec == 'vorbis':
-        return 'ogg'
-    if codec == 'flac':
-        return 'flac'
 
-    # Container-based fallback (lower priority)
+    # Container-based fallback (lowest priority)
-    if container in ('mp4', 'm4a', 'mov', '3gp'):
+    # Ensure the container is in FORMAT_INFO
-        return 'mp4'
+    if container in FORMAT_INFO:
-    if container in ('matroska', 'webm'):
+        return container
-        return 'matroska'
-    if container in ('ogg',):
-        return 'ogg'
-    if container in ('mp3', 'mpeg'):
-        return 'mp3'
-    if container == 'flac':
-        return 'flac'
-    if container == 'wav':
-        return 'wav'
-    if container == 'aac':
-        return 'aac'
-    if container == 'opus':
-        return 'opus'
-    if container == 'amr':
-        return 'amr'
 
     return None
 

web/backend/api/formats.py

@@ -1,8 +1,9 @@
+# web/backend/api/formats.py
 """Endpoint to expose format information to the frontend."""
 
 from fastapi import APIRouter
 
-from backend.constants import FORMAT_INFO
+from audio_splitter.constants import CONTAINER_INFO, CODEC_INFO
 
 router = APIRouter(prefix="/api", tags=["formats"])
 
@@ -10,16 +11,9 @@ router = APIRouter(prefix="/api", tags=["formats"])
 @router.get("/formats")
 async def get_formats():
     """
-    Return the list of supported container formats with their properties.
+    Return the list of supported containers and codecs.
     """
     return {
-        "formats": [
+        "containers": CONTAINER_INFO,
-            {
+        "codecs": CODEC_INFO,
-                "name": name,
-                "ffmpeg": info["ffmpeg"],
-                "extension": info["ext"],
-                "audio_only": info["audio_only"],
-            }
-            for name, info in FORMAT_INFO.items()
-        ]
     }

web/frontend/src/api/client.ts

@@ -1,5 +1,7 @@
+// web/frontend/src/api/client.ts
+
 import axios from 'axios'
-import { TracklistEntry, SplitOptions, TaskStatus } from '../types'
+import { TracklistEntry, SplitOptions, TaskStatus, FormatsResponse } from '../types'
 
 export const api = axios.create({
   baseURL: '/api',
@@ -68,3 +70,9 @@ export const getRecommendedFormat = async (task_id: string): Promise<{ format: s
   const response = await api.get(`/info/recommended-format/${task_id}`)
   return response.data
 }
+
+// New: fetch containers and codecs
+export const getFormats = async (): Promise<FormatsResponse> => {
+  const response = await api.get('/formats')
+  return response.data
+}

web/frontend/src/components/OptionsPanel.tsx

@@ -16,7 +16,11 @@ import { ExpandMore, ExpandLess } from '@mui/icons-material'
 import { useOptionsStore } from '../stores/optionsStore'
 import { useUploadStore } from '../stores/uploadStore'
 import { useValidationStore } from '../stores/validationStore'
+import { getFormats } from '../api/client'
 
+// ------------------------------------------------------------------------------
+// Section component (collapsible)
+// ------------------------------------------------------------------------------
 interface SectionProps {
   title: string
   children: React.ReactNode
@@ -51,54 +55,70 @@ const Section: React.FC<SectionProps> = ({ title, children, defaultExpanded = fa
   )
 }
 
+// ------------------------------------------------------------------------------
+// Main OptionsPanel component
+// ------------------------------------------------------------------------------
 export const OptionsPanel: React.FC = () => {
-  const { options, setOptions } = useOptionsStore()
+  const {
+    options,
+    setOptions,
+    containers,
+    codecs,
+    setContainers,
+    setCodecs,
+  } = useOptionsStore()
+
   const { hasVideo } = useUploadStore()
   const { formatError, setFormatError } = useValidationStore()
 
-  // Audio-only formats from backend constants (hardcoded for now)
+  // Fetch containers and codecs from backend on mount
-  const audioOnlyFormats = ['mp3', 'm4a', 'ogg', 'opus', 'flac', 'wav', 'aac']
+  useEffect(() => {
+    const fetchFormats = async () => {
+      try {
+        const data = await getFormats()
+        setContainers(data.containers)
+        setCodecs(data.codecs)
+      } catch (err) {
+        console.error('Failed to fetch formats:', err)
+      }
+    }
+    fetchFormats()
+  }, [setContainers, setCodecs])
 
+  // --------------------------------------------------------------
+  // Handlers
+  // --------------------------------------------------------------
   const handleFormatChange = (e: React.ChangeEvent<HTMLInputElement>) => {
     const newFormat = e.target.value
     setOptions({ format: newFormat })
-
-    // Validate format
-    if (audioOnlyFormats.includes(newFormat) && hasVideo && !options.drop_video) {
-      setFormatError(
-        `Format '${newFormat}' does not support video streams. Please enable "Drop video" or choose a container that supports video (e.g., MKV, MP4).`
-      )
-    } else {
-      setFormatError(null)
-    }
   }
 
   const handleDropVideoChange = (e: React.ChangeEvent<HTMLInputElement>) => {
     const checked = e.target.checked
     setOptions({ drop_video: checked })
-    // Re-validate format
+  }
-    if (audioOnlyFormats.includes(options.format) && hasVideo && !checked) {
+
+  const handleChange = (field: string, value: any) => {
+    setOptions({ [field]: value })
+  }
+
+  // --------------------------------------------------------------
+  // Format validation – re-run when relevant state changes
+  // --------------------------------------------------------------
+  useEffect(() => {
+    const selectedContainer = containers.find(c => c.name === options.format)
+    if (selectedContainer?.audio_only && hasVideo && !options.drop_video) {
       setFormatError(
-        `Format '${options.format}' does not support video streams. Please enable "Drop video" or choose a container that supports video (e.g., MKV, MP4).`
+        `Container '${options.format}' does not support video streams. Please enable "Drop video" or choose a container that supports video (e.g., MKV, MP4).`
       )
     } else {
       setFormatError(null)
     }
-  }
+  }, [containers, options.format, options.drop_video, hasVideo, setFormatError])
-
-  // Re-validate when hasVideo changes (e.g., after upload)
-  useEffect(() => {
-    const shouldShowError = audioOnlyFormats.includes(options.format) && hasVideo && !options.drop_video
-    const newError = shouldShowError
-      ? `Format '${options.format}' does not support video streams. Please enable "Drop video" or choose a container that supports video (e.g., MKV, MP4).`
-      : null
-
-    // Only update if the error state actually changes
-    if (newError !== formatError) {
-      setFormatError(newError)
-    }
-  }, [hasVideo, options.format, options.drop_video, formatError, setFormatError])
 
+  // --------------------------------------------------------------
+  // Render
+  // --------------------------------------------------------------
   return (
     <Paper sx={{ p: 3 }}>
       <Typography variant="h6" sx={{ mb: 2 }}>
@@ -111,9 +131,12 @@ export const OptionsPanel: React.FC = () => {
         </Alert>
       )}
 
-      {/* Output Settings */}
+      {/* ------------------------------------------------------------------------
+          Output Settings
+      ------------------------------------------------------------------------ */}
       <Section title="Output Settings" defaultExpanded>
         <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
+          {/* Container dropdown */}
           <TextField
             label="Container"
             select
@@ -126,18 +149,14 @@ export const OptionsPanel: React.FC = () => {
               formatError || "Determines the output file extension and container structure."
             }
           >
-            <MenuItem value="mp3">MP3 (.mp3)</MenuItem>
+            {containers.map((container) => (
-            <MenuItem value="m4a">M4A (.m4a)</MenuItem>
+              <MenuItem key={container.name} value={container.name}>
-            <MenuItem value="mkv">MKV (.mkv)</MenuItem>
+                {container.name.toUpperCase()} ({container.extension})
-            <MenuItem value="mp4">MP4 (.mp4)</MenuItem>
+              </MenuItem>
-            <MenuItem value="ogg">OGG (.ogg)</MenuItem>
+            ))}
-            <MenuItem value="opus">OPUS (.opus)</MenuItem>
-            <MenuItem value="flac">FLAC (.flac)</MenuItem>
-            <MenuItem value="wav">WAV (.wav)</MenuItem>
-            <MenuItem value="aac">AAC (.aac)</MenuItem>
           </TextField>
 
-          {/* Transcode option – remains unchanged but clearly labeled */}
+          {/* Audio Codec (Transcode) dropdown */}
           <TextField
             label="Audio Codec (Transcode)"
             select
@@ -148,11 +167,16 @@ export const OptionsPanel: React.FC = () => {
             helperText="Select an audio codec to re-encode, or keep 'Copy' to preserve the original."
           >
             <MenuItem value="">Copy (no transcoding)</MenuItem>
-            <MenuItem value="libmp3lame">MP3 (LAME)</MenuItem>
+            {codecs
-            <MenuItem value="aac">AAC</MenuItem>
+              .filter(c => c.supports_transcoding)
-            <MenuItem value="libopus">OPUS</MenuItem>
+              .map((codec) => (
+                <MenuItem key={codec.name} value={codec.ffmpeg}>
+                  {codec.name.toUpperCase()} (→ {codec.recommended_container})
+                </MenuItem>
+              ))}
           </TextField>
 
+          {/* Drop video stream (only shown if video present) */}
           {hasVideo && (
             <FormControlLabel
               control={
@@ -165,6 +189,7 @@ export const OptionsPanel: React.FC = () => {
             />
           )}
 
+          {/* Drop subtitle streams */}
           <FormControlLabel
             control={
               <Switch
@@ -177,7 +202,9 @@ export const OptionsPanel: React.FC = () => {
         </Box>
       </Section>
 
-      {/* Filename Settings */}
+      {/* ------------------------------------------------------------------------
+          Filename Settings
+      ------------------------------------------------------------------------ */}
       <Section title="Filename Settings">
         <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
           <TextField
@@ -233,7 +260,9 @@ export const OptionsPanel: React.FC = () => {
         </Box>
       </Section>
 
-      {/* Metadata Settings */}
+      {/* ------------------------------------------------------------------------
+          Metadata Settings
+      ------------------------------------------------------------------------ */}
       <Section title="Metadata Settings">
         <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
           <TextField
@@ -289,7 +318,9 @@ export const OptionsPanel: React.FC = () => {
         </Box>
       </Section>
 
-      {/* Tracklist Settings */}
+      {/* ------------------------------------------------------------------------
+          Tracklist Settings
+      ------------------------------------------------------------------------ */}
       <Section title="Tracklist Settings" defaultExpanded>
         <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
           <TextField
@@ -304,9 +335,4 @@ export const OptionsPanel: React.FC = () => {
       </Section>
     </Paper>
   )
-
-  // Helper function for option updates
-  function handleChange(field: string, value: any) {
-    setOptions({ [field]: value })
-  }
 }

web/frontend/src/stores/optionsStore.ts

@@ -1,6 +1,7 @@
 // web/frontend/src/stores/optionsStore.ts
+
 import { create } from 'zustand'
-import { SplitOptions } from '../types'
+import { SplitOptions, ContainerInfo, CodecInfo } from '../types'
 import {
   DEFAULT_FORMAT,
   DEFAULT_OUTPUT_TEMPLATE,
@@ -21,6 +22,17 @@ import {
   DEFAULT_TRACKLIST_FORMAT,
 } from '../constants/generated'
 
+// Extend the state
+interface OptionsState {
+  options: SplitOptions
+  containers: ContainerInfo[]
+  codecs: CodecInfo[]
+  setOptions: (options: Partial<SplitOptions>) => void
+  setContainers: (containers: ContainerInfo[]) => void
+  setCodecs: (codecs: CodecInfo[]) => void
+  reset: () => void
+}
+
 const DEFAULT_OPTIONS: SplitOptions = {
   format: DEFAULT_FORMAT,
   transcode_to: DEFAULT_TRANSCODE_TO ?? '',
@@ -41,17 +53,20 @@ const DEFAULT_OPTIONS: SplitOptions = {
   tracklist_format: DEFAULT_TRACKLIST_FORMAT,
 }
 
-interface OptionsState {
-  options: SplitOptions
-  setOptions: (options: Partial<SplitOptions>) => void
-  reset: () => void
-}
-
 export const useOptionsStore = create<OptionsState>((set) => ({
   options: { ...DEFAULT_OPTIONS },
+  containers: [],
+  codecs: [],
   setOptions: (newOptions) =>
     set((state) => ({
       options: { ...state.options, ...newOptions },
     })),
-  reset: () => set({ options: { ...DEFAULT_OPTIONS } }),
+  setContainers: (containers) => set({ containers }),
+  setCodecs: (codecs) => set({ codecs }),
+  reset: () =>
+    set({
+      options: { ...DEFAULT_OPTIONS },
+      containers: [],
+      codecs: [],
+    }),
 }))

web/frontend/src/types/index.ts

@@ -51,3 +51,22 @@ export interface SplitResponse {
   task_id: string
   status: string
 }
+
+export interface ContainerInfo {
+  name: string
+  ffmpeg: string
+  extension: string
+  audio_only: boolean
+}
+
+export interface CodecInfo {
+  name: string
+  ffmpeg: string
+  recommended_container: string
+  supports_transcoding: boolean
+}
+
+export interface FormatsResponse {
+  containers: ContainerInfo[]
+  codecs: CodecInfo[]
+}