1 files changed, 80 insertions, 0 deletions
diff --git a/app/dl_formats.py b/app/dl_formats.py
new file mode 100644
index 0000000..d0af344
--- /dev/null
+++ b/app/dl_formats.py
@@ -0,0 +1,80 @@
+def get_format(format: str, quality: str) -> str:
+    """
+    Returns format for download
+
+    Args:
+      format (str): format selected
+      quality (str): quality selected
+
+    Raises:
+      Exception: unknown quality, unknown format
+
+    Returns:
+      dl_format: Formatted download string
+    """
+    final_fmt = ""
+
+    if format.startswith("custom:"):
+        final_fmt = format[7:]
+    else:
+        final_fmt = _get_final_fmt(format, quality)
+
+    return final_fmt
+
+
+def get_opts(format: str, quality: str, ytdl_opts: dict) -> dict:
+    """
+    Returns extra download options
+    Mostly postprocessing options
+
+    Args:
+      format (str): format selected
+      quality (str): quality of format selected (needed for some formats)
+      ytdl_opts (dict): current options selected
+
+    Returns:
+      ytdl_opts: Extra options
+    """
+    if "postprocessors" not in ytdl_opts:
+        ytdl_opts["postprocessors"] = []
+
+    if format == "mp3":
+        extra_args = {}
+        if quality != "best":
+            extra_args = {"preferredquality": quality}
+        ytdl_opts["postprocessors"].append(
+            {"key": "FFmpegExtractAudio", "preferredcodec": "mp3", **extra_args},
+        )
+
+    return ytdl_opts
+
+
+def _get_final_fmt(format: str, quality: str) -> str:
+    vfmt, afmt, vres = "", "", ""
+
+    if format in ("mp4", "any"):
+        # video {res} {vfmt} + audio {afmt} {res} {vfmt}
+        if format == "mp4":
+            vfmt, afmt = "[ext=mp4]", "[ext=m4a]"
+
+        if quality == "audio":
+            final_fmt = "bestaudio/best"
+        else:
+            if quality in ("best", "audio"):
+                vres = ""
+            elif quality in ("1440", "1080", "720", "480"):
+                vres = f"[height<={quality}]"
+            else:
+                raise Exception(f"Unknown quality {quality}")
+            combo = vres + vfmt
+            final_fmt = f"bestvideo{combo}+bestaudio{afmt}/best{combo}"
+    elif format == "mp3":
+        if quality == "best" or quality in ("128", "192", "320"):
+            final_fmt = "bestaudio/best"
+            # Audio quality needs to be set post-download, set in opts
+        else:
+            raise Exception(f"Unknown quality {quality}")
+    else:
+        raise Exception(f"Unkown format {format}")
+
+    return final_fmt