Loudness Normalization, LM1

A complete loudness solution for OTT and music streaming โ€” fully compliant with SB 576.
Eliminate loudness variance between sources with an internationally standardized and award-winning technology.

Loudness Normalization ๋น„์ฃผ์–ผ ์ด๋ฏธ์ง€

Deliver perfectly balanced loudness
across every content and device.

Key Features

Metadata-based โ€œserverโ€“clientโ€ architecture eliminates the need for re-encoding or re-mastering of video or audio assets โ€” unlike conventional file-based loudness solutions.

Side-chain metadata are managed independently, enabling flexible workflows, broad vendor interoperability, and full codec agnosticism.

SB 576-compliant loudness control , even in dynamic ad-insertion (SSAI/DAI) environments.

Device-adaptive target loudness: easily set different loudness targets for each playback environment โ€” e.g., TV (โˆ’24 LUFS) and mobile (โˆ’16 LUFS) โ€” from a single source.

Advanced loudness features -DSLC, EQ-Norm, Anti-Clipping, Transparent Mode- automatically compensate for playback-environment characteristics, EQ response, & device-specific variations.

LM1,
the only internationally standardized side-chain metadata technology for loudness management

Recognized as an international standard under ANSI/CTA-2075.1 and TTA.KO-07.0146, LM1 defines the framework for Loudness for OTT and Streaming for Mobile and Fixed Devices. Recognized as an international standard under ANSI/CTA-2075.1 and TTA.KO-07.0146, LM1 defines the framework for Loudness for OTT and Streaming for Mobile and Fixed Devices.
By adopting the LM1 standard, your platform can deliver an optimal and consistent sound experience across CTA-compliant smartphones (iOS/Android), smart TVs, and in-car audio systems โ€” while ensuring full compliance with SB 576. By adopting the LM1 standard, your platform can deliver an optimal and consistent sound experience across CTA-compliant smartphones (iOS/Android), smart TVs, and in-car audio systems โ€” while ensuring full compliance with SB 576.
Loudness ์ด๋ฏธ์ง€
Loudness ์ด๋ฏธ์ง€

Our product lineup is designed to meet diverse needs and deployment environments.

Our product lineup is designed to meet diverse needs and deployment environments.

  • LM1 Server-Tools

    Analyzes the loudness of various incoming content
    on the server side using the ITU-R BS.1770 standards
    (up to BS.1770-5). Automatically adjusts each file
    to meet the target loudness regulations/requirements
    of different countries and platforms.
    With a single server-side process,
    all distributed content can be loudness-normalized
    โ€” without requiring any client-side processing.

  • LM1 Server-Client

    The server measures the loudness of content,
    generates LM1 metadata, and transmits it
    to the client via a side-chain path.
    The client then performs real-time loudness normalization
    according to the playback environment
    and device-specific target loudness.
    This architecture enables seamless integration
    with ANSI/CTA-2075-compliant devices.

  • LM1 Stand-alone

    A real-time loudness normalization technology
    designed for environments where metadata generation is difficult
    โ€” such as live streaming โ€” or for devices
    that must manage multiple audio sources locally,
    such as smartphones, TVs, and in-car audio systems.
    Delivers superior audio quality compared to
    conventional DRC-based normalization, providing consistent
    and transparent sound across all playback situations.

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FAQ

Frequently Asked Questions about Gaudio Labโ€™s Solutions

  • LM1 can be used with any audio codec because it is an audio codec-independent metadata. For example, it can be used with MP3, AAC, FLAC, etc. that do not have separate loudness metadata.

  • The LM1 standard is designed to be an audio codec-agnostic form of extrinsic metadata that can be used in combination with a variety of audio codecs.

    As such, it can be delivered in a number of ways, depending on the streaming service's approach.

    It can be embedded in a container within the streaming content, or it can be passed as a base64 encoded string along with other metadata embedded in the content.

  • It is challenging to extract metadata in real-time with the LM1 in live broadcasting scenarios.

    In the LN SDK, there is a mode (LCO) that can handle loudness normalization without metadata, which is usually sufficient. However, there are some limitations in hitting the exact target loudness.

  • The server is only responsible for extracting and transmitting the LM1 metadata. Once the LM1 metadata is extracted for each sound source, no further processing for loudness leveling is required on the server.

    When playing the sound source, the client receives the LM1 metadata and uses it to process the loudness level in real-time.

  • The LM1 decoder includes a built-in DRC function, which enables comfortable loudness normalization with controlled dynamic range regardless of the listening environment, whether it's a noisy environment like a bus or subway, or when you need to listen quietly like in a quiet room.

  • This standard, established by the American National Standards Institute (ANSI) and the Consumer Technology Association (CTA), defines the loudness normalization method required when playing streaming media such as OTT and OVD so that it can be played at a normalized loudness across various devices and playback environments, enabling users to consume content without inconvenience.

    It emphasizes the use of metadata for loudness normalization, and Gaudio Lab's LM1 metadata standard is also reflected in ANSI/CTA-2075.1, an extended standard of ANSI/CTA-2075.

  • LM1 is a standard that specifies how the information required for the loudness normalization should be made into metadata and defined as a bitstream.

    It was first established in 2020 as a standard specification of the Korea Telecommunications Technology Association (TTA) (TTAK.KO-07.0146) and was reflected in ANSI/CTA-2075.1 in 2022.

    It is designed to solve the loudness problem of streaming media such as OTT, music, and podcasts, and the LM1 metadata specification enables easy loudness management on playback devices.