A decoder includes circuitry configured to receive a current block, determine the current block is a block for updating an unavailable reference frame based on the current block, and update the unavailable reference frame using the current block. Related apparatus, systems, techniques, and articles are also described.

According to the disclosure of the present document, a recovery point picture order count (POC) for a gradual decoding refresh (GDR) picture is derived on the basis of GDR-related information, and an output for pictures related to the GDR picture is determined on the basis of the recovery point POC. The recovery point DOC can be derived on the basis of a syntax element related to the recovery point POC.

According to the disclosure of the present document, a recovery point picture order count (POC) for a gradual decoding refresh (GDR) picture is derived on the basis of GDR-related information, and an output for pictures related to the GDR picture is determined on the basis of the recovery point POC. The recovery point DOC can be derived on the basis of a syntax element related to the recovery point POC.

A signaling of at least one characteristic for layers of a multi-layered video signal such as, for example, for each layer the indication of dependent layers to which the respective layer directly relates via inter-layer prediction, or the signaling of the afore-mentioned second inter-dependency syntax structure, is described. A maximum syntax element is signaled within the multi-layered video signal to indicate a maximally used value of an extension layer-ID field of the packets of the multi-layered video signal, the scope of the maximum syntax element being, for example, a predetermined portion of the multi-layered video signal extending, for example, across several portions of the multi-layered video signal. Accordingly, it is feasible for devices such as decoders or network elements receiving the multi-layered video signal to gain, for a relatively large predetermined portion of the multi-layered video signal, knowledge about the actually consumed portion of the possible domain of possible values.

A signaling of at least one characteristic for layers of a multi-layered video signal such as, for example, for each layer the indication of dependent layers to which the respective layer directly relates via inter-layer prediction, or the signaling of the afore-mentioned second inter-dependency syntax structure, is described. A maximum syntax element is signaled within the multi-layered video signal to indicate a maximally used value of an extension layer-ID field of the packets of the multi-layered video signal, the scope of the maximum syntax element being, for example, a predetermined portion of the multi-layered video signal extending, for example, across several portions of the multi-layered video signal. Accordingly, it is feasible for devices such as decoders or network elements receiving the multi-layered video signal to gain, for a relatively large predetermined portion of the multi-layered video signal, knowledge about the actually consumed portion of the possible domain of possible values.

A method for encoding multiple descriptions for a media stream includes: determining, for a current block of the media stream, a first number of duplicate blocks, determining, for the current block, a plurality of complementary forward gain factors, and determining a first number of descriptions for the current block by applying the plurality of complementary forward gain factors to the first number of duplicate blocks. A method for decoding multiple descriptions for a media stream includes: determining, for a current block of the media stream, a first number of descriptions from the media stream, in which each description comprises a scaled block corresponding to the current block, determining backward gain factors for the first number of scaled blocks, and determining the current block by applying the backward gain factors to the first number of scaled blocks.

A method for encoding multiple descriptions for a media stream includes: determining, for a current block of the media stream, a first number of duplicate blocks, determining, for the current block, a plurality of complementary forward gain factors, and determining a first number of descriptions for the current block by applying the plurality of complementary forward gain factors to the first number of duplicate blocks. A method for decoding multiple descriptions for a media stream includes: determining, for a current block of the media stream, a first number of descriptions from the media stream, in which each description comprises a scaled block corresponding to the current block, determining backward gain factors for the first number of scaled blocks, and determining the current block by applying the backward gain factors to the first number of scaled blocks.

A method is provided that includes receiving pictures of a video sequence in a video encoder, and encoding the pictures to generate a compressed video bit stream that is transmitted to a video decoder in real-time, wherein encoding the pictures includes selecting a picture to be encoded as a delayed duplicate intra-predicted picture (DDI), wherein the picture would otherwise be encoded as an inter-predicted picture (P-picture), encoding the picture as an intra-predicted picture (I-picture) to generate the DDI, wherein the I-picture is reconstructed and stored for use as a reference picture for a decoder refresh picture, transmitting the DDI to the video decoder in non-real time, selecting a subsequent picture to be encoded as the decoder refresh picture, and encoding the subsequent picture in the compressed bit stream as the decoder refresh picture, wherein the subsequent P-picture is encoded as a P-picture predicted using the reference picture.

A method is provided that includes receiving pictures of a video sequence in a video encoder, and encoding the pictures to generate a compressed video bit stream that is transmitted to a video decoder in real-time, wherein encoding the pictures includes selecting a picture to be encoded as a delayed duplicate intra-predicted picture (DDI), wherein the picture would otherwise be encoded as an inter-predicted picture (P-picture), encoding the picture as an intra-predicted picture (I-picture) to generate the DDI, wherein the I-picture is reconstructed and stored for use as a reference picture for a decoder refresh picture, transmitting the DDI to the video decoder in non-real time, selecting a subsequent picture to be encoded as the decoder refresh picture, and encoding the subsequent picture in the compressed bit stream as the decoder refresh picture, wherein the subsequent P-picture is encoded as a P-picture predicted using the reference picture.

Methods and systems for non-destructive, stabilization-based encoder optimization. A video item to be provided to one or more users of a platform is identified. An indication of a motion is identified between an initial video frame of a video sequence associated with the video item and a subsequent video frame of the video sequence. One or more motion stabilization transformations are applied to the video item to modify the motion between at least the initial frame and the subsequent frame. Upon applying the one or more motion stabilization transformations to the video item, the video item is encoded. The encoded video item and one or more instructions to cause the client device to reverse the one or more motion stabilization transformations applied to the video item after decoding the encoded video item are transmitted to a client device connected to the platform.