A method of encoding a sequence of video images into a single video stream with dynamic bitrate, the method comprising: encoding (S110; S420) the sequence of video images into frames of a base layer of the single video stream using a base layer resolution and a base layer compression level; encoding (S120; S430) all video images of the sequence of video images corresponding to respective times before detecting a trigger into a first set of frames of an extended layer of the single video stream, wherein the first set of frames are empty frames irrespective of the encoding of the corresponding frames of the base layer, wherein the empty frames are frames which have been encoded using skip blocks for all blocks of each of the frames, wherein the skip blocks are blocks which each only includes an indication that the block is a skip block, wherein a skip block is a block for which no additional information is provided for enhancement in relation to a corresponding block of a corresponding frame of the base layer, and wherein the trigger indicates that video images of the sequence of video images corresponding to respective times after the trigger may include information that will be of more interest than the video images of the sequence of video images corresponding to respective times before the trigger, wherein the frames of the first set of frames of the extended layer are inter frames encoded using prediction dependent on corresponding frames of the base layer; detecting (S130; C425) the trigger; and only upon detecting (S130; C425) the trigger, encoding (S140; S440) the video images of the sequence of video images corresponding to respective times after detecting the trigger into a second set of frames of the extended layer of the single video stream using a higher resolution than the base layer resolution or a lower compression level than the base layer compression level, wherein the frames of the second set of frames of the extended layer are inter frames encoded using prediction dependent on corresponding frames of the base layer. encoding (S110; S420) the sequence of video images into frames of a base layer of the single video stream using a base layer resolution and a base layer compression level; encoding (S120; S430) all video images of the sequence of video images corresponding to respective times before detecting a trigger into a first set of frames of an extended layer of the single video stream, wherein the first set of frames are empty frames irrespective of the encoding of the corresponding frames of the base layer, wherein the empty frames are frames which have been encoded using skip blocks for all blocks of each of the frames, wherein the skip blocks are blocks which each only includes an indication that the block is a skip block, wherein a skip block is a block for which no additional information is provided for enhancement in relation to a corresponding block of a corresponding frame of the base layer, and wherein the trigger indicates that video images of the sequence of video images corresponding to respective times after the trigger may include information that will be of more interest than the video images of the sequence of video images corresponding to respective times before the trigger, wherein the frames of the first set of frames of the extended layer are inter frames encoded using prediction dependent on corresponding frames of the base layer; detecting (S130; C425) the trigger; and only upon detecting (S130; C425) the trigger, encoding (S140; S440) the video images of the sequence of video images corresponding to respective times after detecting the trigger into a second set of frames of the extended layer of the single video stream using a higher resolution than the base layer resolution or a lower compression level than the base layer compression level, wherein the frames of the second set of frames of the extended layer are inter frames encoded using prediction dependent on corresponding frames of the base layer.