MMS Overview

About Multimedia Messaging Service

MMS (Multimedia Messaging Service) is an extension of the SMS standard. It is a rich multimedia messaging technology which provides audio, video, images and thousands of characters of text within a single message.

Content and messages sent via MMS are delivered to and opened within a recipient’s inbox in the same familiar way as SMS. There is no software to download or application to launch, and end users can reply to an MMS with an SMS, and vice-versa via the same short or code.

Each message is a multimedia presentation. Because MMS uses the cellular network for delivery, a data connection isn’t needed. A majority of U.S. subscription contracts include MMS in an unlimited messaging plan. These combined characteristics make it a simple and convenient method of sending and receiving rich content.

From a carrier or aggregator perspective, MMS is more complex to support and requires greater bandwidth. Media format types and message size limitations vary by carrier and mobile device capabilities. As a result, it costs more to send an MMS than an SMS.

Every mobile phone is pre-configured with settings for how the phone sends and receives MMS messages. For example, an MMS video message that runs in .mp4 format will not open on many Blackberry phones, which only run .3gp video files. Transcoding services optimize the delivery of MMS. These services help solve the technical issues associated with handsets and MMSCs (carrier processing centers) as well as carrier message size limitations. Transcoding services are available on both A2P and P2P routes with different feature sets, and varying costs.

MMS message delivery takes longer than SMS due to both the mms file size, and the network handling complexities. Expect an auto response to typically take between eight and thirty seconds to return an MMS once the keyword has been received by the application.

Quick Facts

There are two important standards that define MMS technology, one published by the 3GPP (3GPP TS 23.140), and the other a series of MMS specifications published by the Open Mobile Alliance (OMA). These two standard bodies cooperate to define the MMS protocols.

An MMS message is:

  • A multimedia presentation in a single entry*
  • Network independent
  • A messaging application that does not require a data plan
  • Supported by MMS-compatible feature phones, smart phones and tablets**

*Some mobile devices will store rich media separate from text.

**MMS Service may not be compatible with all handsets

Key Markets

Key vertical markets with significant growth potential for MMS include:

  1. Retail (brands and agencies)
  2. Social networking and portals
  3. Finance
  4. Insurance
  5. Real Estate
  6. Medical (pharmacy)
  7. Entertainment
  8. Mapping Services
  9. Travel and hospitality

Implementing MMS

There are a few key factors to consider before getting started with MMS. The following requirements are unique to Multimedia Messaging Systems:

  1. Certification: a 16-week process neither precluded by nor included within SMS certification
  2. Fees: Separate from SMS
  3. System Logic: “device discovery” message logic required in MMS systems
  4. Transcoding: due to the varied capabilities of different mobile devices
  5. API: MM4 and/or HTTP specifications
  • Carriers: Verizon, Sprint, T-Mobile and AT&T
  • Rates: MMS is an upgrade service to SMS, with an independent setup and monthly service fee, MMS-specific message rates and carrier surcharge rates.
  • Plans: When using a short code for MMS delivery, an SMS plan is needed in most cases to support an MMS program, as the carriers require SMS opt-in and opt-out messages as well as a recipient’s handset discovery message flow that checks for compatibility prior to sending MMS content.
  • A2P Route: Available via shared short code.
  • P2P Route: Available via US-Registered long code (a premium product with a higher monthly lease rate). Use cases are limited to non-marketing, non-bulk, unique, personalized messages per send.
  • MMS Protocols: HTTP
  • DLR: Supported
  • Incoming Keyword Matching: Supported

General MMS Tips

  • For video avoid complex or gradated backgrounds
  • For video, avoid background noise
  • Keep videos under 40s in length
  • Keep text copy enticing and brief despite longer character capacity

Input File Formats

Without Transcoding Service

Content TypeFile Format

Plain Text without Transcoding

  • Charsets Available: UTF-8, US-ASCII

Transcoded Video

Aspect/Parameter TypeLimit
File FormatWe accept many formats, but prefer .mov, .mpeg,.m4v
Max file size150 MB
Aspect ratio4:3
FormatNon-interlaced, shot in progressive format, orde-interlaced in post
Frames Per Second16(variable)
Pixel ratioSquare
Resolution640 x 480
Border Margins20% in pixels
Max Length40 seconds
Bit Rate96 kbps (variable)
Video Encoding TypeMPEG 4 Simple Profile 0, 1
Audio Encoding TypeQCELP, AMR, EVRC
File Extension3g2, mp4, 3gp, qcp
MIME Typevideo/3gpp2,video/3gpp
Max Message SizeSee Carrier Support
Max Characters1000

Note: If you plan to include written TEXT in the video, leave 20%margins around all text

Transcoded Images

Aspect/Parameter TypeLimit
Size640px x 480px
Border Margins20% in pixels

Note: For GIF Files, if you are planning on using more than 100 frames loop, please consider a supported video format rather than an image/gif format.

Transcoded Audio

Aspect/Parameter TypeLimit
File typeaif, aiff, au, mp3, mp4, wav
Qualityhigh bitrate
Length3-4min max

Carrier MMS File Size Limitations

Short Code

All carriers listed below support both MMS-MT and MMS-MO delivery direction.

CarrierSubject Characters LimitDLR Lists Device TypeMax File Size SupportedTranscoding Supported
Verizon Wireless83Yes1.2 MBYes
AT&T128No1 MBYes
Sprint37Yes2 MBSometimes*
T-Mobile40No3 MBYes

*Sprint does not transcode MMS MOs. However, devices often perform transcoding on their own prior to sending MMS in order to reduce media sizes. Sprint does transcode MMS MTs, but skips transcoding for iPhone and newer Android devices.

Subject Characters Limit

The “Subject” referred to in this field is the subject, header, title or topic of the message. Thus, this refers not to the characters limit of the message body, but of the characters limit for the “subject.”

DLR Lists Device Type

In the table above, the Delivery Receipts of the carriers listed as “yes” for this value will return end-user handset information such as device manufacturer and model within their DLR.


The handling of MMS differs from device to device and MMSC to MMSC. Aecrialink optimizes media file storage and delivery to ensure successful delivery to and viewing by the end-user. Multimedia message content will be received, processed and transcoded in device-specific, single input content files in order to simplify content management and message delivery while retaining high quality and maximum scalability.

Aerialink’s MMS Format Transcoding is an upgrade service with its own cost structure. Contact your Aerialink Account Manager for more information.

via Short Code

How It Works

  1. Prior to sending an MMS, the content is uploaded for transcoding in its base format and a reference ID is provided.
  2. The service uses presets (see below) which define output files that are stored in an external cloud for access during messaging.
  3. When transcoding is completed, a web service callback is created containing a reference ID to the content upload.
  4. Then, when the message is sent, Aerialink makes an API call to the cloud with the transcode reference ID, MDN and destination carrier.
  5. The device type is queried for the MDN and from there the most suitible file format for both the content and destination device is selected.
  6. Aerialink receives the encoded file from the cloud for delivery to the carrier.
  7. The carrier network delivers high-quality content via MMS to the end-user’s device.
  8. Delivery confirmation is returned once the message and all associated content are delivered to the destination handset.

Presets are the transcoded content file templates. Example, one input mp4 video file will be converted to 50+ output video files based on these presets (varying in file type, size, encoding, bit rate, resolution etc). For a given MDN (mobile directory number), our recommendation engine will pick one of these output files and the MMS Gateway will deliver it to the device.


The following features apply to Aerialink’s A2P route for short codes and are performed in advance of a message send.

Content Hosting & Storage
  • Hosting: various hosting facilities and Content Delivery Networks
  • Version Storage: via reference to original piece of content
  • Content Delivery: global
  • Identification: unique code for master content and all transcoded versions
  • Relevance: new file formats and custom case-specific formats added on consistent basis.

Device & Content Adaptation

  • Database Variety: 12,000+ devices & capabilities
  • Versions: input content files transcoded into 50+ versions
    • .mp4s
    • h.264 .3gp
    • mpeg4 .3gp
    • streaming .flv
    • m4v
    • compressed .mov
  • Device Adaptability: all of the following are supported and differ per specific end-device and carrier:
    • screen resolutions
    • frame rates
    • codecs
    • bitrates

via Long Code

Transcoding ensures that all messages and their individualized contents properly adapted or “transcoded” in order to satisfy the input restrictions of the receiving MMSC. In the event that the receiving MMSC is unable to handle videos, Aerialink will convert the first frame of the video clip into a still image.


The Aerialink MMS platform assesses recipient network message size thresholds and transcodes real-time modifications to MMS message size to ensure that messages are delivered successfully within the required size constraints of the recipient network.

Supported Conversions via Long Code

Media Format3GPP (GSM) MIME Type3GPP2 (CDMA) MIME TypeFormat Conversions*
Text- text/plain- text/x-vCard- text/x-vCalendar- text/plain- text/x-vCard- text/x-vCalendarCharacter encoding contains a subset of the logical characters in Unicode (e.g. US-ASCII, ISO-8859-1, UTF-8, GSM 7-bit alphabet, Shift_JIS)UTF-8 used if destination handset does not support cahracter setTreats unrecognized subtypes of “text” as subtype “plain” as long as the MMS terminal MIME knows how to handle charsetTreats all other unrecognized charsets as “application/octet-stream”
Speech- audio/AMR- audio/x-amr- audio/amr-wb- audio/amr-nb- audio/AMR- audio/QCELP- audio/EVRC- audio/SMVSupports both 3GPP2 13K and AMR speech codecsDefault for 3GPP/GSM is AMRIf destination handset does not support AMR, defauflt transcoding will be QCELP 13K (for 3GPP2/CDMA)
Audio- text/x-iMelody- audio/iMelody- audio/x-wav- audio/wav- audio/rmf- audio/x-rmf- audio/basic- text/x-iMelody- audio/iMelody- audio/x-wav- audio/wavSupports MPEG-4 AAC Low Complexity and Long-Term Prediction object typesSampling rate does not exceed 48 kHzChannel configurations supported are mono (1/0) and stereo (2/0)
Synthetic Audio- audio/mid- audio/midi- audio/x-midi- audio/sp-midi- audio/mid- audio/midi- audio/x-midi- audio/sp-midiSupports Scalable Polyphony MIDI (SP-MIDI) content format defined in Scalable Polyphony MIDI specification with device requirements defined in Scalable Polyphony MIDI Device 5-to-24Supports general MIDI Level 1 with minimum of 24 voices
Still Image- image/jpeg- image/jfif- image/jpeg- image/jfifSupports ISO/IEC JPEG and JFIFSupport for ISO/IEC JPEG only applies if:1. Supports baseline DCT, non-differential, Huffman coding as defined in table B1 symbol “SOFO”2. Supports progressive DCT, non-differential, Huffman coding, as defined in table B1, symbol “SOF2”
Bitmap Graphics- image/gif- image/vnd.wap.wbmp- image/png- image/x-png- image/bmp- image/x-bmp- image/gif- image/vnd.wap.wbmp- image/png- image/x-png- image/bmp- image/x-bmpSupports GIF87a, GIF89a and PNG
Video- video/3gpp- video/3gpp2- video/mpg- video/3gpp- video/3gpp2- video/mpgSupports decoding of ITU-T Recommendation H.263 profile 0, level 10; MPEG-4 Visual SImple Profile Level 0; H.263 profile3, level 10Default for 3GPP/GSM is H.263 baselineDefault for 3GPP2/CDMA is MPEG-4
Vector GraphicsSupports “Tiny” profile for Scalable Vector Graphics (SVG - Tiny)Supports the “Basic” profile for Scalable Vector Graphics (SVG - Basic)
Dynamic Media FormatSupports .3g2 formatWhen any media is stored in the .3g2 format, all other media types containedi n the MMS message that have a sample entry defined in .3g2 format are also stored in the .3g2 format.

\Sometimes referred to as transcoding or adaptation*

This page was last updated 1493833605000