From 14dbb924e19ee5b5b943edb724c24a93c4dc1a2f Mon Sep 17 00:00:00 2001
From: bymyself <cbyrne@comfy.org>
Date: Sat, 8 Aug 2026 20:28:57 -0700
Subject: [PATCH] Use PyAV's own predicate instead of querying supported codecs

OutputContainer.supported_codecs only keeps codecs for which
avformat_query_codec returns 1, while add_stream_from_template rejects
only a falsy result. Muxers that implement neither a query_codec
callback nor a codec_tag table return AVERROR_PATCHWELCOME, so they
accept a stream copy that supported_codecs reports as impossible: an
h264 mpegts source saved with format=auto was fully re-encoded and
silently rehoused in mp4.

Attempt the copy and let PyAV answer instead. All streams are added
before the first packet is muxed, so a stream the destination rejects
is caught before anything is written. Handling it per stream also means
a subtitle track the destination cannot store is dropped on its own
rather than diverting the video alongside it into a needless re-encode.

Log the whole-file re-encode at warning, since it is lossy and discards
the extra audio and subtitle streams the transcode path does not carry.
---
 comfy_api/latest/_input_impl/video_types.py | 38 +++++++++------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/comfy_api/latest/_input_impl/video_types.py b/comfy_api/latest/_input_impl/video_types.py
index d35318c7a..b08a6fc9a 100644
--- a/comfy_api/latest/_input_impl/video_types.py
+++ b/comfy_api/latest/_input_impl/video_types.py
@@ -100,17 +100,6 @@ def write_output_metadata(container: InputContainer, output, metadata: dict | No
             output.metadata[key] = value if isinstance(value, str) else json.dumps(value)
 
 
-def unsupported_remux_codecs(streams, output_container) -> list[str]:
-    supported = output_container.supported_codecs
-    return [
-        stream.codec_context.name
-        for stream in streams
-        if isinstance(stream, (av.VideoStream, av.AudioStream, SubtitleStream))
-        and stream.codec_context is not None
-        and stream.codec_context.name not in supported
-    ]
-
-
 def mp4_output_open_kwargs(path: str | io.BytesIO, format: VideoContainer, codec: VideoCodec) -> dict:
     if format != VideoContainer.AUTO and format != VideoContainer.MP4:
         raise ValueError("Only MP4 format is supported for now")
@@ -521,15 +510,6 @@ class VideoFromFile(VideoInput):
     ) -> bool:
         streams = container.streams
         with av.open(path, **open_kwargs) as output_container:
-            unsupported = unsupported_remux_codecs(streams, output_container)
-            if unsupported:
-                logging.info(
-                    "Cannot copy %s into a %s container; re-encoding instead.",
-                    ", ".join(sorted(set(unsupported))),
-                    output_container.format.name,
-                )
-                return False
-
             # Add metadata before writing any streams
             write_output_metadata(container, output_container, metadata)
 
@@ -540,7 +520,23 @@ class VideoFromFile(VideoInput):
                     if stream.codec_context is None:
                         logging.warning("Skipping %s stream %d with unsupported codec", stream.type, stream.index)
                         continue
-                    out_stream = output_container.add_stream_from_template(template=stream, opaque=True)
+                    try:
+                        out_stream = output_container.add_stream_from_template(template=stream, opaque=True)
+                    except ValueError:
+                        codec_name = stream.codec_context.name
+                        format_name = output_container.format.name
+                        if isinstance(stream, SubtitleStream):
+                            logging.warning(
+                                "Dropping %s subtitle stream %d: the %s container cannot store it.",
+                                codec_name, stream.index, format_name,
+                            )
+                            continue
+                        logging.warning(
+                            "The %s container cannot store %s, so the whole file is being re-encoded to H.264/AAC. "
+                            "Any additional audio or subtitle streams will be dropped.",
+                            format_name, codec_name,
+                        )
+                        return False
                     stream_map[stream] = out_stream
 
             # Write packets to the new container