Supported Proxy Video Format [VE OG]

Format specification

VidiEditor requires a proxy video to preview the media assets in the browser based frontend allowing work from anywhere even on lower bandwidth. The VidiEditors streaming server supports following video formats, considering usage of 16 by 9 videos as input.

Reference Documents: AFN-100, RDD-25

Container: MXF, MP4

Video Codec : H.264 Baseline Profile, 2000 kbps constant, Progressive scan

Video Frame Rates: 25, 30, 50, 29.97, 59.94

Video resolution: 640x360 pixels

Audio: AAC, 48 kHz, 192 kbps up to 8x stereo

Anyway the usage of videos is not limited to 16:9 videos only. Having a system with video content having different aspect ratios such as 16:9, 9:16 or 1:1 VidiEditor allows to mix those videos on a timeline as long as they are in the same frame rate. In result it is easy to use video content from traditional linear television (Camera, SDI) mixed with videos coming for example from a mobile phone.

Please note that upon the activation of the VidiEditor service, your VidiCore Starter or Team instance was provisioned with a transcode preset shape-tag built to match the requirements with the default configuration. Read more here: Configurations applied to Vidispine to enable VPMS MediaEditor

Transcoder Recommendation

While the above video format specifications work in general with VidiEditor, it should be mentioned that an aligned chain between proxy generation and media streaming is recommended to get the best results and performance out of the product. This is due to the fact that the smart rendering, used for timeline playback is optimized on specific parameters of the video codec, such as the GOP structure and encoder- and decoder settings. Therefore, the VidiEditors streaming backend is optimized on 2 transcoders used:

1. VidiCoder using a shape tag as described below

2. Transcoder S4M using Nablet decoder settings with mp4 and mxf RDD25 files

Anyway the solution would also work on files generated with different transcoders using above format specification. It might be that performance and accuracy drop when using a different transcoder.

In case a different transcoder solution is needed in specific scenarios it can be helpful to get in contact with the VidiEditor’s product management to clarify differences on concrete examples.

Usage of Proxy Videos

The proxy video format is only used for preview in the source and timeline player components of VidiEditor to allow low bandwidth preview. When a publish action is performed, a newly created file will be transcoded based on the original shape. It is highly recommended to ensure the original and proxy shapes consist of the same frame rate to avoid frame rate conversion on publish.

Also the VidiEditor internal search filters for items having a correct shape. Only items are displayed in the search result having a shape matching the configuration of the ME_ProxyShapeTag in the me_user group key value metadata.

Configuring a shape not matching the above mentioned requirements for video files will result in the player not working in VidiEditor.

Configuring a Shape Tag

The aforementioned default shape tag to generate proxy videos is inserted during VidiEditor’s installation. It is defined as follows:

<TranscodePresetDocument xmlns="http://xml.vidispine.com/schema/vidispine">
    <format>mp4</format>
    <audio>
        <codec>aac</codec>
        <bitrate>192000</bitrate>
        <framerate>
            <numerator>1</numerator>
            <denominator>48000</denominator>
        </framerate>
        <channel>0</channel>
        <channel>1</channel>
        <channel>2</channel>
        <channel>3</channel>
        <channel>4</channel>
        <channel>5</channel>
        <channel>6</channel>
        <channel>7</channel>
        <stream>2</stream>
        <stream>2</stream>
        <stream>2</stream>
        <stream>2</stream>
    </audio>
    <video>
        <scaling>
            <width>640</width>
            <height>360</height>
            <targetDAR>
                <horizontal>16</horizontal>
                <vertical>9</vertical>
            </targetDAR>
        </scaling>
        <codec>h264</codec>
        <bitrate>2000000</bitrate>
        <preset>baseline</preset>
        <setting>
            <key>interlace_flag</key>
            <value>progressive</value>
        </setting>
    </video>
    <thumbnailPlugin>scenechange</thumbnailPlugin>
    <metadata/>
</TranscodePresetDocument>

To add or modify shape tags in VidiCore please read the general VidiCore documentation: https://apidoc.vidispine.com/latest/item/shape-tag.html.