This specification assumes a working knowledge of the Ogg bitstream document.
Identification header is the only packet on the first logical Ogg page and marked "beginning of stream" in the page flags.
| Name | Size (Bytes) | Description |
|---|---|---|
| HDRID | 1 | Header identifier 0x4F |
| ID | 4 | VP9 Identifier VP90 or {0x56, 0x50, 0x39, 0x30} |
| HDRTYPE | 1 | Stream info header type 0x01 |
| VMAJ | 1 | Mapping major version, break compatibility. This specification define major version 1 |
| VMIN | 1 | Mapping minor version, backward compatible. This specification define minor version 0 |
| FW | 2 | Frame width |
| FH | 2 | Frame height |
| PARN | 3 | Pixel aspect ratio numerator |
| PARD | 3 | Pixel aspect ratio denominator |
| FPSN | 4 | Frame rate numerator |
| FPSD | 4 | Frame rate denominator |
Unless otherwise noted, integers are unsigned and encoded in big endian byte order. Newer minor versions of this specification might append new fields to this structure.
A single comment header, if available, beginning on the second page of the logical stream and may span one or more pages.
| Name | Size (Bytes) | Description |
|---|---|---|
| HDRID | 1 | Header identifier 0x4F |
| ID | 4 | VP9 Identifier VP90 or {0x56, 0x50, 0x39, 0x30} |
| HDRTYPE | 1 | Comment header type 0x02 |
| SPACE | 1 | 0x20 |
| VORBISCOMMENT | * | Vorbis comments |
The structure of VORBISCOMMENT metadata is defined in the Ogg Vorbis I format specification.
Newer minor versions of this specification may define new headers that will
start with the HDRID and ID, implemetations should ignore HDRTYPE they
not recognize. Any possible HDRTYPE values are reserved and might be defined
in later versions of this specification.
The granule position of these first pages containing only headers is zero.
The first video frame packet must begin on a new page and must be a keyframe. The last page is marked "end of stream" in the page flags.
An Ogg page may contain one or more Ogg packets.
-------------------------------------- -----------------------------
| page | | page |
-------------------------------------- -----------------------------
| packet | packet | packet | packet | | packet | packet | packet |
-------------------------------------- -----------------------------
A packet may span multiple pages if necessary.
---------------------------------- ----------------------------------
| page | | page |
---------------------------------- ----------------------------------
| very la.. | | ..rge packet |
---------------------------------- ----------------------------------
One Ogg packet must contain exactly one VP9 frame with no additional data.
---------------------------------- --------------------------
| page | | page |
---------------------------------- --------------------------
| frame | frame | frame | frame | | frame | frame | frame |
---------------------------------- --------------------------
VP9 keyframe packets should start a new Ogg page and should be the only packet in a page.
---------------- -------------------------------- ----------------
| page | | page | | page |
---------------- -------------------------------- ----------------
| keyframe | | p-frame | p-frame | p-frame | | keyframe |
---------------- -------------------------------- ----------------
The granule position of a page represents the end position of the last packet completed on that page.
The granule position for VP9 stream contains following fields:
MSB LSB
-----------------------------------------------
| pts | inv_count | dist | resv |
-----------------------------------------------
| 63 32 | 31 30 | 29 3 | 2 0 |
- pts: End of presentation timestamp as frame count of the last complete packet in the Ogg page.
- inv_count: Number of invisible VP9 frame since the last visible frame. For visible frame all bits are set.
- dist: Distance, in packets to the last key frame.
- resv: Reserved for future use.
This specification define VP9
show_existing_framepacket as a non keyframe and is visible.
- Ogg bitstream format specification
- Vorbis comment specification