## 3 Multimedia
### Challenges and Metrics of Study in Multimedia  
In the realm of multimedia transmission in VANET, one of the challenges encountered relates to the sheer volume of data involved, which poses a significant demand for extensive bandwidth. This becomes particularly challenging in DSRC communication networks, where bandwidth resources are limited to 2300 bytes [2; 26]. When considering the compression and transmission of various forms of multimedia content such as images, audio, videos, or audio-visual materials, a fundamental concept of compression, encoding, and bitstream comes into play [27]. A bitstream represents a continuous flow of meticulously organized binary information, serving as a representation of encoded data. Within this bitstream lies the encapsulated version of the compressed or encoded image, audio, or video content [28]. To ensure the successful transmission of this bitstream from its source to its intended destination, it is crucial to give careful consideration to various technical challenges. This involves establishing appropriate metrics, as demonstrated in Table 1, for effectively evaluating the transmission's performance [1; 29]. In VANET multimedia communication, the successful transmission of the bitstream, which represents the encoded multimedia content, is crucial for ensuring high-quality multimedia experiences. This transmission is influenced by the interplay between Quality of Service (QoS) and Quality of Experience (QoE). QoS parameters, such as bandwidth availability, latency, packet loss, and reliability, impact the performance of the communication network and the successful delivery of the bitstream. QoE, on the other hand, focuses on the user's satisfaction with the received multimedia content, considering factors like visual and auditory quality, synchronization, and overall user experience. To optimize QoS and QoE in VANET, more studies should be geared towards techniques such as efficient compression algorithms, traffic prioritization, adaptive streaming, error resilience mechanisms, and QoS-aware routing protocols. An extensive survey, as presented by [1], investigates the correlation between Quality of Experience (QoE) and Quality of Service (QoS) models, specifically within the context of video streaming over vehicular ad hoc networks (VANETs). This work offers a comprehensive examination of these interconnected factors. The authors scrutinize various existing models and techniques for evaluating QoE and QoS metrics in the context of video streaming. The survey addresses the challenges and opportunities tied to delivering a satisfactory streaming experience in VANETs, taking into account factors such as network connectivity, bandwidth limitations, and dynamic mobility. The findings enrich our understanding of the relationship between QoE and QoS in VANETs and provide valuable insights for the design of efficient video streaming systems. In line with the views presented by [1; 30] presents real-world measurements and analysis of video transmission over the IEEE 802.11p standard, which is specifically designed for vehicular communication. The authors conducted experiments to evaluate the performance of video streaming in terms of packet loss, delay, and video quality. The authors conducted a series of experiments aimed at evaluating the performance of video streaming, focusing on key aspects such as packet loss, delay, and video quality. The study explores the influence of various parameters, including vehicle speed and transmission power, on the overall video transmission performance. Through their investigation, the researchers shed light on the practical challenges and limitations associated with video streaming over the IEEE 802.11p standard. Additionally, Ref. [30] introduces a novel approach to video compression by leveraging the Three-Dimensional Discrete Wavelet Transform (3-D DWT) and a unique bit-plane entropy coding method for wavelet sub-band matrices.