Telemadrid begins the simultaneous broadcast of its signal with HDR (High Dynamic Range) quality

Telemadrid has begun to emit its signal with high dynamic range (HDR) intended for ultra high definition receivers and those that have the capacity to reproduce signals with high dynamic range. This signal will be broadcast simultaneously with the now existing quality (HD) signal and will allow users of HDR-capable televisions to enjoy an enhanced viewing experience.

The emission of a television signal with HDR (High Dynamic Range) quality involves the transmission of content with a wider dynamic range y mejorado en comparación con las señales de televisión estándar (SDR).

De las cuatro características técnicas que tienen las emisiones en Ultra alta definición (UHD), que se refieren al rango dinámico, la gama de colores, el número de imágenes por segundo y la resolución, estas nuevas emisiones mejoran los tres primeros aspectos, dejando la resolución, o número de puntos de cada imagen, igual que la alta definición, ya que codificar la emisión con resolución 3840×2160 píxeles, también conocida como 4K, no sería posible con el ancho de banda disponible del apagado de las señales en definición estándar.

Los aspectos clave que mejora la calidad HDR son:

• Extended Dynamic Range HDR (High Dynamic Range). It refers to the dynamic range of the image, that is, the difference between the darkest and brightest areas of an image. HDR expands this range, meaning that details in both dark and bright areas are more visible and realistic. HDR improves image quality by providing a richer, more vibrant visual experience, regardless of image resolution. Telemadrid HDR broadcasting allows for a wider range of brightness and contrast levels compared to standard signals, resulting in a more detailed and realistic image. Simply put, HDR allows TV screens to display more vivid colors, with darker blacks and brighter whites, showing images as objects and scenes are perceived in real life.

• Better color representation. WCG (Wide Color Gamut). This term refers to the ability of a screen or display system to display a wider range of colors than the traditional video standard (Rec. 709). WCG allows for richer, more vibrant color reproduction, resulting in more realistic and visually stunning images. With the WCG, expanding the color range allows us to better adapt to the visualization capacity of the human eye, covering more than 75% of the range of visible colors (compared to the 36% offered by Rec.709), which results in more realistic images.
• Greater number of images per second. HFR (High Frame Rate). This term refers to the frames per second (fps) rate of the video. 50p video means 50 full frames per second are displayed progressively, providing smoother, more fluid reproduction of motion compared to lower frame rates or interlaced scanning. The high frame rate is beneficial for viewing fast action or sports content as it reduces motion blur and improves the overall viewer experience.

When processing higher frame rate signals, (from 25 to 50 images per second), a more efficient coding system is necessary that does not imply increasing the 'bit rate' needs, due to the bandwidth available in the multiplex. To do this, Telemadrid is using the new HEVC encoding that use UHD transmissions, and that is supported by new television models.

As we have mentioned, the last characteristic of UHD signals is 4K resolution and refers to the resolution of the image. 4K offers a higher pixel count compared to standard high definition (HD) resolutions.

4K resolution generally refers to a resolution of 3840x2160 pixels. This means a greater number of pixels, which in order to mean more visible details perceptible by the human eye in the image, certain viewing conditions and distances must be met. While HDR focuses on improving dynamic range y la calidad visual de la imagen, el 4K se enfoca en proporcionar una mayor cantidad de detalles visuales a través de una mayor resolución de imagen.

It is possible to have content that is HDR only, 4K only, or both HDR and 4K simultaneously to offer the best possible quality in terms of dynamic range and resolution. This broadcast will not have 4K resolution.

Para poder disfrutar del contenido HDR, es necesario que el televisor sea compatible con HDR. Esto significa que el equipo receptor debe ser capaz de procesar y mostrar correctamente la señal HDR. Los términos WCG y HFR se refieren a características específicas de la señal de video y pueden ser utilizadas en conjunto con HDR para proporcionar una experiencia visual más completa y de alta calidad. El WCG amplía la gama de colores para una representación más rica y vibrante, y el 50p mejora la suavidad y la calidad del movimiento.

Almost all UHD TVs sold today have this compatibility. Only some 4K TVs sold in the past do not have it. There are several HDR broadcast formats and these broadcasts are made with the HLG curve compatible with most current televisions. Depending on the manufacturer, it will be necessary or not to make some type of adjustment in the configuration of each television, to correctly view this broadcast and achieve the best quality that this format provides.

Esta mejora en la emisión es pionera en España y en el resto del mundo, y abre el camino, como en su momento lo abrió la simultaneidad de las emisiones SD/HD en España, para el largo proceso de migración hacia la Ultra alta definición (Ultra HD).