A method of building a database of geographical locations in a cellular network that have a less-than-desired radio coverage, wherein the method comprises performing the following using a network entity in the cellular network: for a mobile device operating in the cellular network and playing an audio-visual content through an adaptive streaming process, determining a minimum threshold bitrate authorized under the adaptive streaming process; monitoring whether a current audio-visual segment is being delivered to the mobile device at a delivery bitrate that is lower than the authorized minimum threshold bitrate; when the delivery bitrate is lower than the authorized minimum threshold bitrate, obtaining geographic location coordinates for the mobile device; and reporting the geographic location coordinates for storage in the database; wherein determining the authorized minimum threshold bitrate is characterized in : determining whether a manifest file associated with the adaptively delivered audio-visual content is encrypted; if the manifest file is determined to be encrypted, using a default pre-defined bitrate as the authorized minimum threshold bitrate, wherein the default pre-defined bitrate is based on at least one of (i) prior observations of lowest bitrates in unencrypted manifest files associated with content similar in nature to the content currently being delivered; and (ii) actually-used lowest bitrates for delivery of similar content to other users over a given period of time. for a mobile device operating in the cellular network and playing an audio-visual content through an adaptive streaming process, determining a minimum threshold bitrate authorized under the adaptive streaming process; monitoring whether a current audio-visual segment is being delivered to the mobile device at a delivery bitrate that is lower than the authorized minimum threshold bitrate; when the delivery bitrate is lower than the authorized minimum threshold bitrate, obtaining geographic location coordinates for the mobile device; and reporting the geographic location coordinates for storage in the database; wherein determining the authorized minimum threshold bitrate is characterized in : determining whether a manifest file associated with the adaptively delivered audio-visual content is encrypted; if the manifest file is determined to be encrypted, using a default pre-defined bitrate as the authorized minimum threshold bitrate, wherein the default pre-defined bitrate is based on at least one of (i) prior observations of lowest bitrates in unencrypted manifest files associated with content similar in nature to the content currently being delivered; and (ii) actually-used lowest bitrates for delivery of similar content to other users over a given period of time. determining whether a manifest file associated with the adaptively delivered audio-visual content is encrypted; if the manifest file is determined to be encrypted, using a default pre-defined bitrate as the authorized minimum threshold bitrate, wherein the default pre-defined bitrate is based on at least one of (i) prior observations of lowest bitrates in unencrypted manifest files associated with content similar in nature to the content currently being delivered; and (ii) actually-used lowest bitrates for delivery of similar content to other users over a given period of time. <EOS>