draft-ietf-avt-uncomp-video-05.txt   draft-ietf-avt-uncomp-video-06.txt 
Internet Engineering Task Force AVT WG Internet Engineering Task Force AVT WG
INTERNET-DRAFT Ladan Gharai INTERNET-DRAFT Ladan Gharai
draft-ietf-avt-uncomp-video-05.txt USC/ISI draft-ietf-avt-uncomp-video-06.txt USC/ISI
Colin Perkins Colin Perkins
University of Glasgow University of Glasgow
27 January 2004 16 February 2004
Expires: August 2004
RTP Payload Format for Uncompressed Video RTP Payload Format for Uncompressed Video
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
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For 8, 10, 12 or 16 bit samples, the pgroup is formed from four For 8, 10, 12 or 16 bit samples, the pgroup is formed from four
adjacent pixels (6, 15, 9 or 12 octets respectively). adjacent pixels (6, 15, 9 or 12 octets respectively).
For YCbCr 4:2:0 video, the Cb and Cr components are sub-sampled by a For YCbCr 4:2:0 video, the Cb and Cr components are sub-sampled by a
factor of two both horizontally and vertically. Therefore chrominance factor of two both horizontally and vertically. Therefore chrominance
samples are shared between certain adjacent lines. Figure 2 shows samples are shared between certain adjacent lines. Figure 2 shows
the composition of luminance and chrominance samples for a 6x6 pixel the composition of luminance and chrominance samples for a 6x6 pixel
grid of 4:2:0 YCbCr video. The pixel group is a group of four pixels grid of 4:2:0 YCbCr video. The pixel group is a group of four pixels
arranged in a 2x2 matrix. The octet size of the pgroup for arranged in a 2x2 matrix. The octet size of the pgroup for
progressive scan 4:2:0 video with samples sizes of 8, 10, 12 and 16 progressive scan 4:2:0 video with samples sizes of 8, 10, 12 and 16
bits is 6, 5, 9 and 12 octets respectively. For interlaced 4:2:0 bits is 6, 15, 9 and 12 octets respectively. For interlaced 4:2:0
video the corresponding pgroups are 4, 5, 6 and 8 octets. video the corresponding pgroups are 4, 5, 6 and 8 octets.
line 0: Y00 Y01 Y02 Y03 Y04 Y05 line 0: Y00 Y01 Y02 Y03 Y04 Y05
Cb00 Cr00 Cb01 Cr01 Cb02 Cr02 Cb00 Cr00 Cb01 Cr01 Cb02 Cr02
line 1: Y10 Y11 Y12 Y13 Y14 Y15 line 1: Y10 Y11 Y12 Y13 Y14 Y15
line 2: Y20 Y21 Y22 Y23 Y24 Y25 line 2: Y20 Y21 Y22 Y23 Y24 Y25
Cb10 Cr10 Cb11 Cr11 Cb12 Cr12 Cb10 Cr10 Cb11 Cr11 Cb12 Cr12
line 3: Y30 Y31 Y32 Y33 Y34 Y35 line 3: Y30 Y31 Y32 Y33 Y34 Y35
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RTP packets using the payload format defined in this specification RTP packets using the payload format defined in this specification
are subject to the security considerations discussed in the RTP are subject to the security considerations discussed in the RTP
specification [RTP] and any appropriate RTP profile. This implies specification [RTP] and any appropriate RTP profile. This implies
that confidentiality of the media streams is achieved by encryption. that confidentiality of the media streams is achieved by encryption.
This payload type does not exhibit any significant non-uniformity in This payload type does not exhibit any significant non-uniformity in
the receiver side computational complexity for packet processing to the receiver side computational complexity for packet processing to
cause a potential denial-of-service threat. cause a potential denial-of-service threat.
It is important to be note that uncompressed video can have immense It is important to note that uncompressed video can have immense
bandwidth requirements (up 270 Mbps for standard definition video, bandwidth requirements (up 270 Mbps for standard definition video,
and approximately 1 Gbps for high definition video). This is and approximately 1 Gbps for high definition video). This is
sufficient to cause potential for denial-of-service if transmitted sufficient to cause potential for denial-of-service if transmitted
onto most currently available Internet paths. onto most currently available Internet paths.
Accordingly, if best-effort service is being used, users of this Accordingly, if best-effort service is being used, users of this
payload format MUST monitor packet loss to ensure that the packet payload format MUST monitor packet loss to ensure that the packet
loss rate is within acceptable parameters. Packet loss is considered loss rate is within acceptable parameters. Packet loss is considered
acceptable if a TCP flow across the same network path, and acceptable if a TCP flow across the same network path, and
experiencing the same network conditions, would achieve an average experiencing the same network conditions, would achieve an average
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