Clients with whom we’re providing caption or subtitling files for need to provide us with a reference video. Below is an outline of our reference video specs.

If, however, we’re embedding or encoding captions or subtitles into your video, we’ll need a master, not a reference. Check out our master video specs here.

What is a reference video?

A reference video enables you to send us a proxy for your program. By providing us a burned-in timecode, we then have the ability to synchronize your caption with precision. While we prefer an MPEG-1 format, we also accept the following:

  • MP4
  • MOV
  • WMV
  • And others

Things to keep in mind for your burn-in timecode

In order to streamline this process and ensure a perfect final product, the burned-in timecode should be placed at the top of the screen, and each frame should be legible. The frame rate should match the final, and the timecode should match the master or asset.

How to send us your reference video

Metro Audio/Video provides you two options for sending your reference video files: electronically and via mail.

Electronic File Delivery Options:

  • Upload to our FTP site (with SSL encryption available)
  • Allow us to access your FTP, Signiant or Aspera site
  • Send your files via YouSendIt, WeTransfer, Dropbox or other cloud-based methods
  • Directly through our website (ideal for small or single projects). Go to our Client Login to begin uploading your file

You can also send your files, on a DVD-R or hard drive, to our NYC offices.

  • Ship to:
    Attention: Project Manager
    Metro Audio & Video
    240 85th St.
    Brooklyn, NY 11209

If you currently don’t have a project manager, request a quote from us now.

Things to consider prior to sending us your files:

  • If you send us your files via DVD/Blu-ray, the timecode burn-in should match the MPEG-2 asset timecode in the authoring system.
  • If we’re sending you a Final Cut or KONA .mov, the reference video you send us needs to be an .mov file.
  • If you have any other questions regarding your files, feel free to contact your project manager directly.

File Specifications

Below is a list of various set-ups we recommend for our reference videos

MPEG-1 (general settings)
Based on the VCD preset

  • Burned-in timecode matching your asset
  • Video bit rate: 1000 Kb’s
  • Constant Bit Rate
  • GOP (Group of Pictures): IBBPBBPBB
  • B frames between reference: 2
  • P frames n Group of Pictures: 2
  • Audio Encoding: MPEG Layer 2
  • Audio Bit Rate: 256 Kb/s
  • Total Bit Rate: 1.3 Mb/s
  • Size: 320×240 (352×240 is adequate)

Quicktime (general settings)
MOV or MP4

  • Burned-in timecode matching your asset
  • Video:
    • AVC, with constant bit rate, or MPEG-v4 Visual, Simple@L1, with constant bit rate
  • Size: 320×240 (4:3)/480×272 (16:9)
  • Audio:
    •  AAC, LC 128 Kbps, 48kHz
  • File Size: Under 800 MB
  • Test file needed to confirm compatibility

For Video Description

Send a complete .wav file in addition to your reference video

Standard Audio Settings:

  • 48 kHz
  • 24 bit
  • 24 LKFS
  • MONO

We will return the format you send to us.

MPEG-1 settings various software types

Sorenson Squeeze 8.5

Format Constraints: program

Stream Type: VCD MPEG 1


  • MPEG 1 codec
  • 1-Pass CBR
  • 29.97 fps
  • 1000kbps target data rate
  • Pixel Aspect Ratio: CCIR601 525 lines
  • GOP Structure:
    • I frames – 6
    • P frames – 1
    • Auto GOPS – None
  • Frame size: Maintain Aspect Ratio, 352×240
  • Do Half-Pel Search: Yes
  • Timestamps: All Frames


  • Timecode


  • MPEG Layer 2 Audio
  • 224 Kbps data rate
  • 48Hz, stereo 16 bit

Compressor 3.5

  • Apply Timecode Generator filter in Final Cut
  • Video: Auto ratio, Frame rate: 100% of source, Fast deinterlace filter, linear resize filter.
  • Audio: 48 kHz,2 channel, 16bit


  • MPEG1 system stream
  • Video: MPEG1, constrained[1]  parameters (CPB) – 352×240, 1:1 display, 1123200 bits per second
  • Audio: MPEG1 layer2 – stereo, 256kbps. 2 channels, 48hz


  • Must have windowburn matching your asset
  • Must not be authored