Testing system (1, 60) for a video and audio reproduction system (100, 101), comprising: a data source with video and audio data (3, 61) for reproduction by the video and audio reproduction system (100, 101), the video and audio data (3, 61) comprising unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) in every video frame (4, 30 - 37, 62 - 64) and every audio frame (6, 38 - 45, 68 - 70); a recording unit (8, 74), configured to record a video stream and an audio stream generated by the video and audio reproduction system (100, 101) by reproducing the video and audio data (3, 61); and a test processor (11, 79), configured to extract the unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) from the recorded video stream and the recorded audio stream, and to verify if respective unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) of simultaneous video frames (4, 30 - 37, 62 - 64) and audio frames (6, 38 - 45, 68 - 70) have been recorded by the recording unit (8, 74) simultaneously; wherein an audio frame (6, 38 - 45, 68 - 70) is an audio sequence with the length of a respective video frame (4, 30 - 37, 62 - 64) and the unique marks (7, 46 - 53, 71 - 73) in the audio frames (6, 38 - 45, 68 - 70) comprise a sinusoidal sound wave of a respective frequency; wherein the frequencies of the sinusoidal sound waves range from a minimum frequency to a maximum frequency; wherein the frequencies of the sinusoidal sound waves of two consecutive audio frames (6, 38 - 45, 68 - 70) are spaced apart by a first threshold value; wherein the frequencies of the sinusoidal sound waves increase sequentially by the first threshold value until the maximum frequency is reached and then fall back to the minimum frequency plus a second threshold value, and wherein the second threshold value increases with every repetition of the frequency sequence by its starting value. a data source with video and audio data (3, 61) for reproduction by the video and audio reproduction system (100, 101), the video and audio data (3, 61) comprising unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) in every video frame (4, 30 - 37, 62 - 64) and every audio frame (6, 38 - 45, 68 - 70); a recording unit (8, 74), configured to record a video stream and an audio stream generated by the video and audio reproduction system (100, 101) by reproducing the video and audio data (3, 61); and a test processor (11, 79), configured to extract the unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) from the recorded video stream and the recorded audio stream, and to verify if respective unique marks (5, 65 - 67, 7, 46 - 53, 71 - 73) of simultaneous video frames (4, 30 - 37, 62 - 64) and audio frames (6, 38 - 45, 68 - 70) have been recorded by the recording unit (8, 74) simultaneously; wherein an audio frame (6, 38 - 45, 68 - 70) is an audio sequence with the length of a respective video frame (4, 30 - 37, 62 - 64) and the unique marks (7, 46 - 53, 71 - 73) in the audio frames (6, 38 - 45, 68 - 70) comprise a sinusoidal sound wave of a respective frequency; wherein the frequencies of the sinusoidal sound waves range from a minimum frequency to a maximum frequency; wherein the frequencies of the sinusoidal sound waves of two consecutive audio frames (6, 38 - 45, 68 - 70) are spaced apart by a first threshold value; wherein the frequencies of the sinusoidal sound waves increase sequentially by the first threshold value until the maximum frequency is reached and then fall back to the minimum frequency plus a second threshold value, and wherein the second threshold value increases with every repetition of the frequency sequence by its starting value.