Onno Eerenberg

MPEG-2 compliant trick play over a digital interface

Current analog and digital tape based video recorders support trick play mode such as fast search and slow- motion, it is desirable that non-tape based systems have at least the same functionality as the already existing systems. This paper presents an experimental trick-play technique that allows visual search on a remotely locate disk-based storage system connected to a digital TV via a digital interface that resembles the performance of tape-based recorders. Our concept is based avoiding intermediate transcoding of the video signal, but instead re-using the recorded MPEG-2 encoded video. This allows generation of fast search modes in forward and reverse direction, as well as slow-motion in forward direction. A special is introduced, to overcome annoying motion judder when interlaced pictures are re-displayed twice or more. Our experimental results show that the proposed reduced refresh-rate mechanism indeed shows better visual performance than a conventional system without additional processing and it copes with various real-time constraints such as bandwidth, disk seek-rate and CPU load.

IP-recovery in the DVB-H link layer for TV on mobile

Recently, DVB-H Internet Protocol based TV on Mobile devices made its entrance in the mobile arena. Due to transmission over an error-prone channel, IP datagrams (packet at network layer) may be corrupted. To improve reception robustness, the DVB-H link layer is equipped with Forward Error Correction (FEC), allowing correction of erroneous IP datagrams, using two-bit signaling information. During reception, locator information is derived prior to FEC, indicating the storage position of correctly received IP datagrams. This is essential due to the variable-length sizes of the IP-based data. For the situation that FEC fails to correct all erroneously received data, the locator information enables retrieval of all correctly received IP datagrams and indicates the location of potentially corrected IP datagrams. Using the derived locator information, experimental research has shown that after FEC, a considerable number of correct IP datagrams can still be recovered from an incorrect MPE-FEC frame. This results in up to 50% data recovery for medium-sized datagrams. This successful recovery depends on the received IP datagram length and the transmission error probability and results in an improved audiovisual decoding quality.

Efficient Validation/Verification of a Robust DVB-H Link Layer

Currently, various semiconductor manufacturers develop silicon solutions for DVB-H receivers. One of the key functions in a DVB-H receiver is the link layer. In order to differentiate, manufacturers can choose between basic or advanced link-layer implementation concepts, resulting in modest or excellent performance. This paper presents the required validation and verification tools for evaluating the DVB-H link-layer robustness, capable of generating and analyzing extreme signal conditions. Furthermore, we also discuss an advanced analysis tool required to inspect the output IP-based data, service information and program specific information of the link layer. The earlier simulation results for improved link-layer performance presented by the tools are validated from a newly developed silicon implementation.