A user-side content moderation device for content moderation in real-time communication, comprising: a memory; and a processor, the processor configured to execute instructions stored in the memory to: receive a first portion of a media stream from a sending user; determine a classification of the first portion of the media stream using a local content moderation module including a machine-learning module trained to classify content as either appropriate or inappropriate, wherein the classification is indicative of an appropriateness of transmission of the first portion to a receiving user, wherein the classification is one of appropriate, inappropriate, or uncertain, and wherein the classification of uncertain indicates that the first portion cannot be determined with sufficient certainty whether the first portion is appropriate or inappropriate; in response to determining that the first portion is uncertain for transmission to the receiving user, perform instructions to: scale the first portion of the media stream to obtain a scaled first portion of the media stream; transmit, to a centralized content moderation device, the scaled first portion of the media stream, wherein the centralized content moderation device determines a centralized determination of whether the first portion is appropriate; and in response to the centralized determination indicating that the first portion of the media stream is inappropriate: blur the first portion to obtain a blurred first portion; and transmit, to the receiving user, the blurred first portion; and in response to determining that the first portion is appropriate, transmit the first portion to the receiving user. a memory; and a processor, the processor configured to execute instructions stored in the memory to: receive a first portion of a media stream from a sending user; determine a classification of the first portion of the media stream using a local content moderation module including a machine-learning module trained to classify content as either appropriate or inappropriate, wherein the classification is indicative of an appropriateness of transmission of the first portion to a receiving user, wherein the classification is one of appropriate, inappropriate, or uncertain, and wherein the classification of uncertain indicates that the first portion cannot be determined with sufficient certainty whether the first portion is appropriate or inappropriate; in response to determining that the first portion is uncertain for transmission to the receiving user, perform instructions to: scale the first portion of the media stream to obtain a scaled first portion of the media stream; transmit, to a centralized content moderation device, the scaled first portion of the media stream, wherein the centralized content moderation device determines a centralized determination of whether the first portion is appropriate; and in response to the centralized determination indicating that the first portion of the media stream is inappropriate: blur the first portion to obtain a blurred first portion; and transmit, to the receiving user, the blurred first portion; and receive a first portion of a media stream from a sending user; determine a classification of the first portion of the media stream using a local content moderation module including a machine-learning module trained to classify content as either appropriate or inappropriate, wherein the classification is indicative of an appropriateness of transmission of the first portion to a receiving user, wherein the classification is one of appropriate, inappropriate, or uncertain, and wherein the classification of uncertain indicates that the first portion cannot be determined with sufficient certainty whether the first portion is appropriate or inappropriate; in response to determining that the first portion is uncertain for transmission to the receiving user, perform instructions to: scale the first portion of the media stream to obtain a scaled first portion of the media stream; transmit, to a centralized content moderation device, the scaled first portion of the media stream, wherein the centralized content moderation device determines a centralized determination of whether the first portion is appropriate; and in response to the centralized determination indicating that the first portion of the media stream is inappropriate: blur the first portion to obtain a blurred first portion; and transmit, to the receiving user, the blurred first portion; and scale the first portion of the media stream to obtain a scaled first portion of the media stream; transmit, to a centralized content moderation device, the scaled first portion of the media stream, wherein the centralized content moderation device determines a centralized determination of whether the first portion is appropriate; and in response to the centralized determination indicating that the first portion of the media stream is inappropriate: blur the first portion to obtain a blurred first portion; and transmit, to the receiving user, the blurred first portion; and blur the first portion to obtain a blurred first portion; and transmit, to the receiving user, the blurred first portion; and in response to determining that the first portion is appropriate, transmit the first portion to the receiving user.