[media-types] [IANA #1443847] text/cmcd registration req uest

Hi Darrel,

The requester sent this message from the group chair:

===

The reviewer is working from an old v1 version of the spec. In v2, we have removed the JSON response. The mime-type “text/cmcd” is describing the new event data, which is a single string comprised of sets of human readable key-value pairs, separated by the newline character, as the body of a POST request. An example looks like this:

POST body:

bl=(6000),br=(4200;v 256;a),cid="content-id-123",e=t,h="example.com",lb=(523;v 64;a),msd=812,mtp=(87000;v 49000;a),pb=(4200;v 256;a),pt=29188,sf=d,sid="session-id-123",sn=2,st=v,sta=p,tb=(4200;v 256;a),tpb=(4200;v 256;a),ts=1764752430000,v=2

This is designed to be human readable for quick debugging. Each key has a human readable abbreviation. For example ‘bl’ - buffer length, ‘br’ - bitrate, ‘cid’ - content ID etc. Engineers observing the CMCDv2 data in console and debug logs can instantly read it without having to run any sort of application parser. 

We believe text/cmcd is the correct form for the following reasons:

V2 has shifted to a "newline-separated” format string format. Each line follows the same syntax as the v1 headers (e.g., br=2000,bl=5000), but they are stacked vertically. This is fundamentally text-based, not a JSON structure.
The text/ prefix informs the server and middleboxes that the payload is human-readable text. The /cmcd subtype specifically informs the log aggregator or CDN that this isn't just a random "note"—it is a structured CMCD report that needs to be parsed into its respective keys.
 
We would appreciate a re-review in light of the above information. 

https://cta-wave.github.io/Resources/common-media-client-data--cta-5004-a.html

===

Does this work? If it's OK, is the submission OK to approve as-is?

thanks,
Amanda

On Sat Feb 21 20:31:54 2026, [email protected] wrote:
> Why is this a text/* media type?  It sounds a lot like structured
> content rather than text.  I can't tell because the specification
> isn't publicly available, but based on examples in the GitHub repo it
> doesn't look like text for human consumption to me.
> 
> E.g.
> CMCDRequest:bl=21300,dl=18500,mtp=48100,nor="..%2F300kbps%2Ftrack.m4v",nrr="12323-
> 48763",su
> CMCD-Object:br=3200,d=4004,ot=v,tb=6000
> CMCD-Status:bs,rtp=12000
> CMCD-Session:cid="faec5fc2-ac30-11ea-bb37-
> 0242ac130002",pr=1.08,sf=d,sid="6e2fb550-c457-11e9-bb97-
> 0800200c9a66",st=v
> 
> https://github.com/cta-wave/common-media-client-
> data/issues/185#issuecomment-3385947158
> 
> This should just be registered as application/cmcd and the JSON
> variant can be application/cmcd+json.
> 
> Darrel
> 
> ________________________________
> From: Amanda Baber via RT <[email protected]>
> Sent: Wednesday, February 18, 2026 2:43 PM
> Cc: [email protected] <[email protected]>; Darrel Miller
> <[email protected]>
> Subject: [IANA #1443847] text/cmcd registration request
> 
> Hi Darrel,
> 
> Sending a reminder for this request from February 11th.
> 
> thanks,
> Amanda
> 
> On Wed Feb 11 19:11:38 2026, amanda.baber wrote:
> > Hi Darrel,
> >
> > Could you review this registration request for us by February 25th?
> >
> > The CTA has already been approved for standards-tree media type
> > registration.
> >
> > thanks,
> > Amanda
> >
> > =====
> >
> > Name: Alexandra Blasgen
> >
> > Email: [email protected]
> >
> > Media type name: text
> >
> > Media subtype name: cmcd
> >
> > Required parameters: N/A
> >
> > Optional parameters: N/A
> >
> > Encoding considerations: 8bit
> >
> > UTF-8 coded strings
> >
> > Security considerations: The privacy and security concerns are
> > discussed in sec. 7 of the CMCDv2 specification.
> >
> > Interoperability considerations: The MIME type describes a
> > standardized "snapshot" of media player state and conditions, and is
> > intended to enable interoperable analysis and monitoring solutions
> > for
> > media distribution.
> >
> > Published specification: This MIME type corresponds to the batch
> > format of the Common Media Client Data specification, CTA-5004.
> > The second version of this specification contains the batch
> > functionality. The final published version of the spec is available
> > at
> > https://www.cta.tech/standards/cta-5004.
> >
> > Applications which use this media: Requests with this MIME type are
> > emitted by media players. The receiving service would typically use
> > these for purposes such as, monitoring and fault analysis.
> >
> > Fragment identifier considerations: N/A
> >
> > Restrictions on usage: N/A
> >
> > Provisional registration? (standards tree only): No
> >
> > Additional information:
> >
> > 1. Deprecated alias names for this type: N/A
> > 2. Magic number(s): N/A
> > 3. File extension(s): cmcd
> > 4. Macintosh file type code: N/A
> > 5. Object Identifiers: N/A
> >
> > General Comments:
> >
> > Person to contact for further information:
> >
> > 1. Name: Alexandra Blasgen
> > 2. Email: [email protected]
> >
> > Intended usage: COMMON
> >
> > Author/Change controller: Consumer Technology Association (CTA)

_______________________________________________
media-types mailing list -- [email protected]
To unsubscribe send an email to [email protected]