Simple Video Converter

Building a video converter in Python using the AVBlocks Transcoder.

Source Video

For a video source we use the Wildlife.mp4 movie from the Internet Archive. The original format is an MP4 container with H.264/AVC video and AAC audio.

Overview

This snippet is a fully functional video converter. It takes Wildlife_h264_aac.mp4 as input and converts it to H.265/HEVC video and AAC audio in an MP4 container, saved as Wildlife_h265_aac.mp4.

Code

"""
Transcode a media file from H.264/AVC to H.265/HEVC.

This sample demonstrates the basic AVBlocks transcoding workflow with
hardcoded input and output file paths.
"""

import sys

from avblocks import (
    Library, MediaInfo, MediaSocket, Transcoder,
    StreamType, StreamSubType
)


def main():
    Library.initialize()

    # Set license information. To run AVBlocks in demo mode, comment the next line out
    # Library.set_license("<license-string>")

    input_file = "Wildlife_h264_aac.mp4"
    output_file = "Wildlife_h265_aac.mp4"

    with MediaInfo() as input_info:
        input_info.inputs[0].file = input_file

        if input_info.open():
            input_socket = MediaSocket.from_media_info(input_info)

            # Start with same output as the input, which is MP4 / H.264 + AAC
            output_socket = input_socket.clone()

            # Get the output video stream info
            out_video_stream = output_socket.pins[0].stream_info

            # Change the video stream type to H.265 (HEVC)
            # and the stream subtype to HEVC Annex B
            out_video_stream.stream_type = StreamType.H265
            out_video_stream.stream_sub_type = StreamSubType.HEVC_Annex_B

            # Input is H.264/AVC at 700 kbps.
            # With H.265/HEVC we can use lower bitrate, e.g. 500 kbps.
            out_video_stream.bitrate = 500000

            # Change the output file name to Wildlife_h265_aac.mp4
            output_socket.file = output_file

            # Create Transcoder and configure it with
            # the input and output sockets
            with Transcoder() as transcoder:
                transcoder.inputs.add(input_socket)
                transcoder.outputs.add(output_socket)

                # Allow demo mode for the transcoder when
                # using the demo version of the library
                transcoder.allow_demo_mode = True

                # Run the transcoder
                if transcoder.open():
                    transcoder.run()
                    transcoder.close()
                else:
                    print(f"transcoder.open() failed: {transcoder.error.message}", file=sys.stderr)
        else:
            print(f"input_info.open() failed: {input_info.error.message}", file=sys.stderr)

    Library.shutdown()
    return 0


if __name__ == '__main__':
    sys.exit(main())

The code is from the simple_converter sample.

How to run

Follow the steps in the Quick Start for Linux, macOS or Windows, but in hello.py use the code from this article.

Download the Wildlife.mp4 sample file as Wildlife_h264_aac.mp4 and save it in the project directory:

# Linux and macOS
curl \
  -L -o Wildlife_h264_aac.mp4 \
  https://archive.org/download/WildlifeSampleVideo/Wildlife.mp4

# Windows
Invoke-WebRequest `
  -Uri https://archive.org/download/WildlifeSampleVideo/Wildlife.mp4 `
  -OutFile Wildlife_h264_aac.mp4

Run the application:

python hello.py

Wait for the Transcoder to finish - it will take a few minutes. The converted file Wildlife_h265_aac.mp4 will be in the project directory.