Using the H.264 specification for anywhere, anytime placeshifted video - Embedded.com

Using the H.264 specification for anywhere, anytime placeshifted video

Video is everywhere, available to users of handheld devices with Internet broadband access virtually any time, any place, and in many formats. One of the major consumer electronics industry challenges in recent years has been to conveniently, seamlessly, and consistently deliver video across a broad range of formats. The solution is 'placeshifting', which allows consumers to watch live or DVR-recorded content on any wireless device. Placeshifting enables viewing and listening to live, recorded, or pre-stored media on a remote device (computer, tablet, mobile phone, or TV) over the Internet or over a data network.

To stream mobile-device-friendly, full HD-resolution content requires the use of transcoding technology because mobile devices cannot handle MPEG-2. Transcoding adjusts the bit rate required to send the stream over a low-bandwidth network. The optimal transcoder can output the stream for any mobile device.

The latest placeshifting technologies use the proven H.264 standard, with its successful application in handheld devices including today’s popular smart phones and small cameras. Compact, low-power ICs now allow widespread deployment of products capable of playing H.264/AVC video at standard definition and with HD TV resolutions. In these handheld and mobile devices, H.264 combines high quality with low memory sizes, allowing for seamless video.

As the most widely used video-encoding format, H.264 now supports the HTML5 video tag, and is supported on every Blu-ray digital video disc (DVD) player, plus most Flash and Silverlight players. The format’s efficient hardware-acceleration capability delivers excellent, high-definition video even on inexpensive mobile and handheld products. The decoding takes place inside the processor; no additional software support is required.

Another H.264 benefit is the ability to use video taken directly from a camera on the web with no need to encode it. This is significant because the same video with different encoding typically needs additional software support, consuming power and slowing the process.

The H.264 standard: benefits and advantages
Since its inception almost 10 years ago, the H.264/MPEG-4 Part 10 standard or AVC (Advanced Video Coding) has become one of the most commonly used formats for the recording, compressing, and distributing high-definition video. This block-oriented, motion-compensation-based codec standard has been successful worldwide because it can record for long time periods without needing extra disk space. The H.264 specification lowers costs, significantly increases the amount of video that can be archived, and reduces the amount of redundant recording.

Earlier compression methods let users record excellent picture quality at real-time frame rates, but these methods required large hard drive capacity, with wasted disk space. H.264 uses predictive technology, which reduces redundant video recording. For example, instead of constantly recording a room under surveillance where there is no motion, H.264 uses prior recordings and images that remain in place until some action or motion changes the scene or setting. If someone walks into an empty room that is being monitored, H.264 systems will record the change in the room, and use the previously recorded background where applicable.

There are other benefits to H.264. Its sampling rates run up to 32 frames of video to ensure complete accuracy and quality, compared with previous compression methods that typically apply only one or two frames as a reference.

Along with conserving hard disk space, products using the standard bring together high quality video and low memory sizes for seamless presentations of video when transmitted. The video image is extremely stable, and the audio is always synchronized. As a result, broadcast companies around the globe have rapidly adopted the H.264 standard, and its flexibility makes it likely it will be used for a long time.

Mobile devices and placeshifting
To meet the audio and video specifications of playback equipment, the ideal H.264-compliant device provides robust and reliable bidirectional H.264/MPEG transcoding of audio data for multiple formats. Transrating adds the ability to convert H.264 video data into H.264 formats of various video resolutions and bit rates.

The ICs needed to enable the technology must be flexible, so they can fit the various formats, resolutions, and bit rates that differ throughout the world. For example, Japan and the United States use MPEG-2 for broadcasting, while Europe, South America, and most of continental Asia use the H.264 specification.

Power requirements also have to be minimized, and footprints need to be compact. New generations of devices reduce power consumption below 1.2W when using the H.264 transrating function in full, high-definition mode. This is achieved by using miniaturization technologies and by incorporating memory into the device. As with many other audio and video ICs, the small footprint makes it possible to use the devices in home electronics equipment, smart phones, and other mobile and portable equipment.

In addition to full HD transcoding functionality, next generationdevices feature H.264 transrating functionality for converting H.264video data into highly compressed data (Figure 1 ). These devices can also transcode audio data for any format, meeting the specifications of the playback equipment.

Figure 1: The complete system block of the Fujitsu solution includes I/F bridge, transcoder, and OFDM plus RF.

Asan example, Fujitsu’s proprietary transcoding technology deliversindustry-leading levels of low power consumption and integrates 1GB ofFast Cycle RAM (FCRAM). The built-in memory technologies andminiaturization process technologies hold power consumption to 1.2W.Connecting two tuner modules to two tuner input terminals enablessimultaneous control of a program as it is being viewed and of anotherprogram as it is being recorded.

Figure2: The Fujitsu interface bridge SoC incorporates 10 differentinterfaces including USB, Serial ATA, PCI Express, Ethernet MAC, TS andother interfaces, all on a single chip.

Suchdevices also reduce the delay time required during transcoding, whichspeeds distribution over a network. This represents a significantimprovement over the first-generation transcoding products that havebeen widely used in home electronics equipment and mobile products todeal with format-conversion issues while maintaining good video quality.

Since demand for wireless distribution of HD content to mobiledevices is growing rapidly, the new H.264 transcoding devices have beendesigned to meet the specific requirements of multiple regions andbandwidth constraints. The built-in memory architectures lower powerconsumption, overcoming thermal effects, enable small form-factorproduct design, and minimize the BOM cost.

Figure 3: The Fujitsu solution features built in transcoder, low power, and control functions in a small form factor.

Transcodingsolutions can be integrated into accessories as simple and flexible as aUSB dongle. Video streaming to mobile devices can be achieved using aWi Fi router with a TV tuner for standalone or mobile devices, or a PVRwith a built-in HDD and Blu-ray / HDD recorder. The technology also canbe applied in a PCTV with a mini-card for notebook PCs and in aUSB/PCI-e TV tuner accessory.

In devices such as the exampleFujitsu solution, two streams for recording to HDD and mobile flashdrives can be created simultaneously. The transcoder enables thedevelopment of various PC accessories because of its ultra-small packageand low power requirements. The device can also be installed insmall-footprint products like mini-cards, due to its embedded memory.

Thecombination of low power requirements, compact footprint, embeddedmemory, and transcoding functionality enable the placeshifting and othercapabilities required to bring all the benefits of H.264 to mobileproducts.

Anthony Wong is a senior marketing managerwith Fujitsu Semiconductor America in Sunnyvale, Calif. He has more than15 years experience in the semiconductor industry. He is currentlyengaged in application specific standard product marketing.

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