To deliver IPTV in HD or 4K quality requires high video compression, using codecs like H.264 or H.265. These formats significantly reduce file sizes, but they also increase the sensitivity to packet loss, and can extend the zap time way past 20 seconds.

1. 1
FASTCHANNELCHANGE(FCC)

2. What it does?
• To deliver IPTV in HD or 4K quality requires high video compression, using codecs
like H.264 or H.265. These formats significantly reduce file sizes, but they also
increase the sensitivity to packet loss, and can extend the zap time way past 20
seconds.
• Fast Channel Change (FCC) brings the zap time back to less than a second and
UDP Retransmission (RET) resends lost video packets to eliminate image and
audio distortion.
• Time to change channel without FCC : 2 to 4 seconds
• Time to change channel with FCC : < 1 second (Broadcasting has additional delay)

3. Why normal channel change is slow?
• Waiting for a Random Access Point (RAP):
• Video content can be encoded efficiently by taking advantage of the dependencies of picture
frames with respect to previous or subsequent picture frames in the video stream.
• Receiver must wait for what is called an intra-encoded picture (I-picture) or RAP before the
decoder can start processing. The periodicity of the RAPs in the video stream will hence
impact the channel change response time.
• Video Buffer filling time at the receiver:
• Before a video stream (starting with a RAP) gets decoded, it is first buffered. There is a trade-
off to be considered between video quality and the (maximum) amount of buffering required
at the receiver.
• If the maximal allowed buffer is very small (small delay), then the video quality will suffer,
especially in fast moving scenes
• CAS/DRM, packet loss repair, multicast switching time (IPTV), STB signal
processing delays, etc.

4. FCC features and Benefits
• FCC and UDP RET with guaranteed performance regardless of number and
mix of request
• Runs on a purpose-built TV Server, which can be deployed at the network
edge to offload traffic and save costs
• Instant scalability through license keys of up to 20 Gbps output and 4 Gbps
ingest per 1U server
• Easy integration with set-top box clients (RFC compliant)
• MTBF of 10 years for easy operation and minimal operating expense
• Less than a second zap time
• Less than 100W power consumption at max load

5. How it works
1. FCC server receives and caches IP multicast
streams
2. UDP RET corrects image and audio
distortion due to packet loss by resending
lost video packets
3. During a channel change, the FCC server
initiates a unicast burst to the viewer’s set-
top box (STB) for a quick reference frame
delivery
4. The STB seamlessly switches over to the
live multicast for continuous play, while the
FCC server terminates the unicast burst
5. This results in an amazing viewing
experience with a fast and seamless
channel change.

6. How it works
Working of FCC
Architecture of IPTV

7. • There are two techniques for
compressing the FCC unicast stream
in time to allow the unicast session
to catch up to the multicast stream:
bursting and denting.
• When bursting, the stream is sent at
a rate faster than multicast stream,
for example, the stream can be
‟bursted” at 130% (or 30% over the
nominal) multicast rate.
• ‟Denting” is a technique where less
important video frames are dropped
by the FCC server and not sent to
the FCC client. Hybrid mode
combines bursting and denting.
FCC work flow.

8. FCC unicast stream compressing