MPEG Transport Streams Packetized Digital Video Over IP Jon M. Beaulieu INFSY 560 Dec 07, 2015 Cricket IP Front Back 2 Cricket IP • Applications: – MPEG Transport Stream (TS) monitoring and validation. – Measure performance of the Media Delivery Index (MDI) IP flow. – Measure Internet Group Management Protocol (IGMP) performance. • Specs: – Used for MPEG-2 as well as SD/HD over SPTS (single program) and MPTS (multi program). – Continuously monitors up to 10 IP unicast or multicast flows w/ deep MPEG packet inspection. – Bandwidth monitoring via 10/100 Mb Ethernet ports. – Information correlation of multiple network probes. – 80 MB buffer for video capture. 3 System Status L3: - IP address - subnet mask - gateway IP L4: - Upload Port # - Mgmt Port # 4 The Transport Stream Packet TS header = 4 bytes Sync Error Start Program Identifier Continuity Priority Flags Byte indicator Indicator (PID) Counter 8 bits 1 bit 1 bit 1 bit 13 bits 4 bits 4 bits Data payload will be either: Transport - Video Data payload header - Audio - Data 4 bytes 184 bytes TS packet = 188 bytes 5 PIDs and PATs/PMTs Program Map Program Association Table (PMT) 1 Table (PAT) PID = 0 Video PID = 26 Program Map Table 1 Main Audio PID = 17 Program Map Table 2 Second Audio Program Map PID = 32 Program Map Table (PMT) 2 Table n Video PID = 12 Main Audio PID = 44 Second Audio PID = 20 6 The IP packet Transport Header • Sync byte • Error Indicator Transport TS packet: Data payload header • Start Indicator = 188 bytes • Priority • PID 4 bytes 184 bytes • Continuity Counter MPEG Transport Stream = 1,316 bytes Encapsulated IP packet Ethernet IP UDP MPEG Stream CRC = 1,366 bytes header header header 46 bytes 188 bytes 4 bytes 7 Unicast vs Multicast Unicast: Multicast: Signal Signal Source Source Private One-to-One Non-private One-to-Many communication communication The signal source copies A network device (router) the signal copies the signal 8 Unicast vs Multicast with Cricket Unicast vs Multicast Packet size Frame Check Sequence (FCS) Percentage of bandwidth utilized 9 Types of Video Streams • An Elementary Stream (ES) is the basic MPEG-encoded format. Not useful for IP. • A Packetized Elementary Stream (PES) is an elementary stream broken into packets. • A Program Stream (PS) has variable bit rates, several PES’s, but a single program. • A Transport Stream (TS) uses fixed-length packets, several PES’s, multiple programs. 10 Media Overview with Cricket Network Utilization Video Types MPEG-4 Stream 11 Media Overview with Cricket Active Flows Good Flows 12 Packetizing the Transport Stream Elementary Packetized Transport Streams Elementary Stream Streams MPEG video video packetizer signal encoder MPEG audio Single audio packetizer Transport signal 1 encoder Program Stream Multiplexer MPEG Transport audio audio packetizer Stream signal 2 encoder (SPTS) data Data can be: packetizer - closed captioning - program info - PCR 13 TS Packet Loss • Jitter measures the variation in the arrival time of the TS packets in the IP stream. • Delay Factor (DF) is the cumulative IP jitter (buffer fill/emptying) on an IP network. • Media Loss Rate (MLR) counts the out-of- order or lost packets per second. • Media Delivery Index (MDI) is the standard for measuring media delivery quality. • The Program Clock Reference (PCR) 14 TS Concept: Jitter Transport Stream (ideal) TS packets buffer Ideally, packets arrive: - the same size - at the same rate - with the same interval Transport Stream (reality, with jitter) TS packets buffer buffer overflow buffer underrun lost packet 15 Flow Census with Cricket Color coded alarm indicators 16 Flow Census with Cricket MPEG-4 video signal MDI – total # of sec with Number of Media TS Programs: TS Packet packet loss: - Total Identifiers - 15 minutes - Monitored - 24 hours - Faulted Number of PIDs in TS: MDI - MLR in MDI – total - Total Media TS Media TS - Monitored packets per packets lost: - Faulted sec - 15 minutes - 24 hours 17 Flow Census with Cricket Amount of Streaming bit # of PIDs that buffer (in msec) rate (payload do not appear required to only) in the PAT PID handle jitter structure Various Amount of Program Clock measures for buffer Reference RTP packet (in bytes) (in kbps) loss and required to aka: video TS sequence handle jitter bit rate errors 18 Program Status with Cricket - # of PIDs - Bit Rate statics PIDs for the PMT and PESs - PIDs for the PMT and PESs 19 Flow Statistics with Cricket Highlighting this flow Brings up this metrics window 20 Sources • Ineoquest Technologies, Inc. (October 2009). Cricket IP User’s Guide - HUG-CTIPXX-001. [User’s guide]. • Ineoquest Technologies, Inc. (18 July 2012). Digital Video. [Presentation]. Retrieved 21 Oct 2015 from http://dvac-scte.org/digital-video.pdf. • Ineoquest Technologies, Inc. (n.d.). Quality of Video-over-IP. [White paper]. Retrieved 17 Nov 2015 from http://ftp.ineoquest.com/pub/docs/ Papers/VideoOverIPStreamQuality.pdf. • RFC4445. A Proposed Media Delivery Index (MDI). J. Welch, J. Clark. April 2006. (Format: TXT=24171 bytes) (Status: INFORMATIONAL) (DOI: 10.17487/RFC4445). [Technical paper]. Retrieved 23 Oct 2015 from https://tools.ietf.org/html/rfc4445. • Simpson, W. (2008). Video Over IP. [Book] Burlington, MA. Focal Press. 21.