What causes "Failed to resize video: {str(e)}" in Comfy-Org/ComfyUI?

Read the suffix after 'Failed to resize video:' to identify the root PyAV error.

Comfy-Org/ComfyUI · error · RuntimeError

Failed to resize video: {str(e)}

Error message

Failed to resize video: {str(e)}

What it means

Generic wrapper around any failure inside resize_video (PyAV). The except block closes containers and re-raises as RuntimeError('Failed to resize video: ...'). The inner text is the actual PyAV error — commonly a decode failure, unsupported pixel format, or the explicit 'resize produced no frames' ValueError from the same function.

Source

Thrown at comfy_api_nodes/util/conversions.py:557

                        break
                # Carry odd audio time bases the mp4 muxer rejects; reset pts, encoder assigns clean ones (MP3-in-AVI)
                audio_frame.pts = None
                for packet in audio_stream.encode(audio_frame):
                    output_container.mux(packet)
            for packet in audio_stream.encode():
                output_container.mux(packet)

        output_container.close()
        input_container.close()
        output_buffer.seek(0)
        return InputImpl.VideoFromFile(output_buffer)

    except Exception as e:
        if input_container is not None:
            input_container.close()
        if output_container is not None:
            output_container.close()
        raise RuntimeError(f"Failed to resize video: {str(e)}") from e


def _f32_pcm(wav: torch.Tensor) -> torch.Tensor:
    """Convert audio to float 32 bits PCM format. Copy-paste from nodes_audio.py file."""
    if wav.dtype.is_floating_point:
        return wav
    elif wav.dtype == torch.int16:
        return wav.float() / (2**15)
    elif wav.dtype == torch.int32:
        return wav.float() / (2**31)
    raise ValueError(f"Unsupported wav dtype: {wav.dtype}")


def audio_bytes_to_audio_input(audio_bytes: bytes) -> dict:
    """
    Decode any common audio container from bytes using PyAV and return
    a Comfy AUDIO dict: {"waveform": [1, C, T] float32, "sample_rate": int}.
    """

View on GitHub (pinned to 1c6d8d45b3)

Solutions

Read the suffix after 'Failed to resize video:' to identify the root PyAV error.
If it is 'resize produced no frames', fix start_time/duration (error 764).
Ensure target dimensions are even (yuv420p constraint).
Re-encode the source as standard H.264 MP4 and retry.

Defensive patterns

Strategy: try-catch

Validate before calling

out_w, out_h = target_dims
if out_w % 2 or out_h % 2:
    raise ValueError('yuv420p requires even width and height')

Try / catch

try:
    out = resize_video(video, out_w, out_h, start_time, duration)
except RuntimeError as e:
    if 'resize produced no frames' in str(e):
        out = resize_video(video, out_w, out_h, 0.0, video.get_duration())  # full clip fallback
    else:
        raise

Prevention

Use even target dimensions for yuv420p encodes.
Validate the decode-ability of the source with ffprobe first.
Validate trim windows (see error 764) before resizing.

When it happens

Trigger: resize_video_to_max_pixels / resize_video on corrupted input, a container with no decodable video stream, an encoder rejecting the target dimensions (odd width/height with yuv420p), or the empty-selection ValueError from error 764.

Common situations: Feeding a broken download or a file with a mismatched extension; target resolution with odd dimensions (yuv420p requires even w/h); a very short clip combined with trimming parameters that select no frames.

Related errors

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/47838042c372f338. Report an issue: GitHub.