Add video stream copy remuxing

tools/video_options.py

@@ -175,12 +175,12 @@ def ask_video_codec_options() -> VideoCodecOptions:
             extension = _prompt_container_extension()
         if codec is None:
             codec = _prompt_codec()
-        if crf is None:
+        if codec != "copy" and crf is None:
             default_crf = 16 if codec == "libx264" else 21
             crf = _prompt_int(f"CRF [{default_crf}]: ", default=default_crf)
-        if not preset:
+        if codec != "copy" and not preset:
             preset = _prompt_preset(default="slow")
-        if "MBT_VIDEO_THREADS" not in os.environ:
+        if codec != "copy" and "MBT_VIDEO_THREADS" not in os.environ:
             threads = _prompt_threads(default=None)
     else:
         extension = extension or ".mp4"
@@ -190,8 +190,8 @@ def ask_video_codec_options() -> VideoCodecOptions:
 
     return VideoCodecOptions(
         codec=codec,
-        crf=crf,
-        preset=preset,
+        crf=crf if crf is not None else 21,
+        preset=preset or "slow",
         extension=extension,
         profile=profile,
         level=level,
@@ -249,7 +249,6 @@ def ask_audio_options(
     preserve_pitch = ask_audio_pitch_option(has_speed_changes=has_speed_changes)
     if env_mode:
         mode = _normalize_audio_mode(env_mode)
-        _validate_audio_container(mode, container_extension)
         return AudioEncodeOptions(
             mode=mode,
             bitrate=env_bitrate or default_audio_bitrate(mode),
@@ -260,10 +259,9 @@ def ask_audio_options(
         return AudioEncodeOptions(mode="none", preserve_pitch=preserve_pitch)
 
     while True:
-        if container_extension == ".mkv":
-            prompt = "Audio: Enter=Opus, a=AAC, f=FLAC, c=copy/trim audio, n=no audio: "
-        else:
-            prompt = "Audio: Enter=AAC re-encode, c=copy/trim audio, n=no audio: "
+        prompt = "Audio: Enter=" + (
+            "Opus" if container_extension == ".mkv" else "AAC"
+        ) + ", a=AAC, o=Opus, f=FLAC, c=copy/trim audio, n=no audio: "
         answer = prompt_input(prompt).strip().lower()
         if not answer:
             mode = "opus" if container_extension == ".mkv" else "aac"
@@ -271,10 +269,10 @@ def ask_audio_options(
         if answer in {"a", "aac"}:
             mode = "aac"
             break
-        if container_extension == ".mkv" and answer in {"o", "opus"}:
+        if answer in {"o", "opus"}:
             mode = "opus"
             break
-        if container_extension == ".mkv" and answer in {"f", "flac"}:
+        if answer in {"f", "flac"}:
             mode = "flac"
             break
         if answer in {"c", "copy"}:
@@ -329,11 +327,6 @@ def _normalize_audio_mode(value: str) -> str:
     raise RuntimeError("MBT_VIDEO_AUDIO must be aac, opus, flac, copy, or none")
 
 
-def _validate_audio_container(mode: str, container_extension: str) -> None:
-    if container_extension == ".mp4" and mode in {"opus", "flac"}:
-        raise RuntimeError("MP4 output supports aac, copy, or none audio in this tool")
-
-
 def _container_extension_from_env() -> str | None:
     raw = os.environ.get("MBT_VIDEO_CONTAINER", "").strip().lower()
     if not raw:
@@ -369,7 +362,7 @@ def _codec_from_env() -> str | None:
 
 def _prompt_codec() -> str:
     while True:
-        answer = prompt_input("Video codec: x264, Enter=x265: ").strip().lower()
+        answer = prompt_input("Video codec: x264, Enter=x265, c=copy: ").strip().lower()
         if not answer:
             return "libx265"
         try:
@@ -383,7 +376,9 @@ def _normalize_codec(value: str) -> str:
         return "libx264"
     if value in {"x265", "h265", "hevc", "libx265"}:
         return "libx265"
-    raise ValueError("codec must be x264 or x265")
+    if value in {"c", "copy", "streamcopy", "stream-copy"}:
+        return "copy"
+    raise ValueError("codec must be x264, x265, or copy")
 
 
 def _int_from_env(name: str) -> int | None: