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Diffstat (limited to 'docs/native-code/rtp-hdrext/video-layers-allocation00/README.md')
| -rw-r--r-- | docs/native-code/rtp-hdrext/video-layers-allocation00/README.md | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/docs/native-code/rtp-hdrext/video-layers-allocation00/README.md b/docs/native-code/rtp-hdrext/video-layers-allocation00/README.md index c4454d8ee1..cfa8c4cb0d 100644 --- a/docs/native-code/rtp-hdrext/video-layers-allocation00/README.md +++ b/docs/native-code/rtp-hdrext/video-layers-allocation00/README.md @@ -22,6 +22,10 @@ rtp stream (SVC), or independent spatial layers sent on multiple rtp streams ## RTP header extension format +Note: when including the optional width, height and maximum framerate +fields, the total data length of the extension can exceed 16 bytes +and is sent as a two-byte header extension [1] + ### Data layout ``` @@ -68,7 +72,7 @@ alignment. layers. Values are stored in ascending order of spatial id. Zero-padded to byte alignment. -Target bitrate in kbps. Values are stored using leb128 encoding [1]. One value per +Target bitrate in kbps. Values are stored using leb128 encoding [2]. One value per temporal layer. Values are stored in (RTP stream id, spatial id, temporal id) ascending order. All bitrates are total required bitrate to receive the corresponding layer, i.e. in simulcast mode they include only corresponding @@ -78,9 +82,11 @@ temporal layers are also included. Resolution and framerate. Optional. Presence is inferred from the rtp header extension size. Encoded (width - 1), 16-bit, (height - 1), 16-bit, max frame rate 8-bit per spatial layer per RTP stream. Values are stored in (RTP stream -id, spatial id) ascending order. +id, spatial id) ascending order. Only sent when the resolution differs from the +last values, the framerate changed by more than 5fps and on key frames. An empty layer allocation (i.e nothing sent on ssrc) is encoded as special case with a single 0 byte. -[1] https://aomediacodec.github.io/av1-spec/#leb128 +[1] https://www.rfc-editor.org/rfc/rfc8285#section-4.3 +[2] https://aomediacodec.github.io/av1-spec/#leb128 |