QC Test Reference
The tables below contain a list of all of the tests included with Qualify, and information about what each test does and how it can be configured.
File Checks
Deep MXF Tests
Syntax Checks
Enabling syntax checking will test the appropriate codec based on the file provided.
| Check | Identifier | Description |
|---|---|---|
| MPEG-2 Video Codec Syntax | SC-101 | For MPEG-2 streams, section 8.5 (Table 8-13) defines upper limits for bit rate, in Mbps, for each combination of Profile and Level. For MPEG-2 streams, section 8.5 (Table 8-14) of ISO/IEC 13818-2 defines the vbv_buffer size requirements (in bits) for each combination of Profile and Level. |
| AVC/H.264/MPEG-4 Video Codec Syntax | SC-102 | Tests that the sequence should always start with an IDR picture as per ITU-T H.264. Sequences that start with a non-IDR picture can cause playability problems, including tearing, stuttering and freeze frames. Tests that bitstreams do not cause an underflow or overflow in the hypothetical reference decoder (HDR), as per ITU-T H.264, Annex C. Tests that PPS referenced in the headers exist in the file as per ITU-T H.264. Tests that bitstreams do not cause coded picture buffer (CPB) removal timing violations in the hypothetical reference decoder as per ITU-T H.264, Annex C. |
| Transport Stream Syntax | SC-104 | Checks the Transport Stream Syntax and includes these tests:
|
| MP4 HEVC Nal Unit | SC-106 | The test checks for the inconsistent carriage of NAL unit structured video in MP4 format files. An alert will be generated when a byte stream format is found in the MP4 file i.e. when NAL unit start code prefix is found in place of the size of the NAL unit. |
| Dolby-E Audio Codec Syntax | SC-108 | CRC Check: Checks the CRC of each Dolby-E frame. Frames that fail the CRC check are likely corrupted either in transport or in the decoder. Guard Band Alignment: Checks Dolby-E guard band start position against the values from Table 4-2 of the Dolby-E specifications. Guard Band Not In Ideal Position: Checks for a Dolby-E frame that is not in the ideal position in reference Table 4-2 of the Dolby-E specifications. Frame Rate Coherency: Checks for a Dolby-E stream where the frame rate does not match with the container metadata frame rate. Frame Synchronization: Checks for a frame without a synchronization header in the Dolby-E stream. |
Caption / Subtitle Checks
Video Metadata
Video Quality
Audio Metadata
Audio Quality
| Check | Identifier | Description |
|---|---|---|
| Peak Level | AQ-101 | Measures the Peak audio level throughout the program material, and will alert if it is in violation of the user specified value. The user can choose whether to measure as dBFS or dBTP. |
| Phase Coherence | AQ-102 | Measures the phase coherence between channel pairs. Phase is measured on a scale of -1 to 1, where -1 means "completely out of phase" and 1 means "completely in phase/mono". |
| Dual Mono | AQ-103 | Compares two audio streams and will alert if dual mono sections are detected between them. Max Allowed Duration is the total amount of dual mono allowed in the file, measured in the specified Max Allowed Units. Duration units can be samples, milliseconds, seconds or percentage. Tolerance Window Duration is where a dual mono section lasting less than this time window will be ignored. For example: |
| Clicks and Pops | AQ-104 | Detects transients or sudden changes in amplitude, such as those caused by noise on a digital or analog signal. The user can choose between low, medium or high sensitivity; high sensitivity is more likely to generate false positive results, but may also detect smaller transients which are deemed erroneous. |
| Clipping | AQ-105 | Detects audio clipping by testing for successive samples of equal value. Quiet samples (those below a fixed small value) are supressed and do not count towards the clipping test. |
| Integrated Loudness (inc Dialog Gating) | AQ-106 | Integrated Loudness is measured over the duration of the file. In calculating the loudness, the arrangement of channels is assumed as found in the Audio Layout settings. Dialog gating can be applied to ITU 1770-1, which will measure loudness only when dialog is present. ITU 1770-2, 1770-3, and 1770-4 options do not currently support dialog gating. |
| Short-term Loudness | AQ-107 | Short-term Loudness is measured over a sliding rectangular time window. The measurement is not gated. The default window length of 3 seconds corresponds to EBU-Tech 3341 short-term mode. The Max Violations setting will report only the worst violation, in accordance with EBU-Tech 3341/EBU r128. The All Violations setting will report all violations. |
| Momentary Loudness | AQ-108 | Momentary Loudness is measured over a 400ms sliding rectangular time window as per EBU-Tech 3341 Momentary mode. The measurement is not gated. The Max Violations setting will report only the worst violation, in accordance with EBU-Tech 3341/EBU r128. The All Violations setting will report all violations. |
| Loudness Range | AQ-109 | Loudness Range is a measurement of the variation in loudness over the duration of a file. The algorithm is specified in EBU-Tech 3342 and produces an output Loudness Range (LRA) in terms of Loudness Units (LU). |
| Minimum Level | AQ-110 | Measures the audio RMS level per channel using a sliding window of the user specified length. If the RMS level for a given channel drops below this level for a contiguous period equal to or longer than the window length, an alert will be raised. Due to the nature of the windowing function, if the period is longer than the window length, only the minimum measurement during the period will be given. |
| Silence | AQ-111 | Detects both intentional and unintentional Silence. The threshold indicates the threshold below which an audio track is considered silent. If Digital Silence is selected, instead of using the threshold, the track is checked for the presence of absence of audio samples. |
| PPM Level | AQ-112 | The peak level according to the "BBC Peak Program Meter" (IEC 60268-10 Type IIa) standard. The meter can operate in MS (sum/difference) mode (modes M3 and M6), or AB mode (individual channels). Note that in MS mode, only the sum is measured.
|
| Channel Position | AQ-113 | Checks whether 5.1 channels are in the correct place by using known frequencies to analyze the baseband of the center and LFE channel and validating against what should be present. |
| Tone | AQ-114 | Checks for the presence of a sine wave tone (a "test tone"), on each channel. Level is in dBFS peak-to-peak. If levels are supplied in RMS, approximately 3dB should be added; for example a -9dBFS RMS signal will measure -6dBFS peak-to-peak. |
| EAS Tone | AQ-115 | Checks for the presence of an EAS (Emergency Alert System) tone. |
| Audio Hiss Detection | AQ-117 | This test applies a low pass filter to the frequency transform of the audio track and determines if tape hiss noise is present. By default, this test is checking for hiss noise across the entire time domain above 15,000 Hz. |
| Audio Hum Detection | AQ-118 | This test applies a high pass filter to the frequency domain of the audio waveform to determine if 50 Hz or 60 Hz hum (mono tone frequency) is present (+/- 1 Hz) anywhere within the clip. |
| Wow and Flutter | AQ-119 | Check if Wow or Flutter is present. Wow is slow, gradual variations in timing or speed and flutter is faster, higher-frequency variations in timing or speed. These are determined by finding a mono frequency tone present in the audio waveform and by analysing audio frequency variations along the average pitch variation curve (PVC). |
| Audio Description | AQ-120 | Checks for an audio description channel on a given mix. User should specify the expected audio description and control channels. In advanced settings, the user can adjust the frequency and amplitude of the control channel as well as their tolerances. The test reports the audio description / control pair (if any) and alerts when it is not found where expected. |
| Channel Mapping | AQ-121 | Checks the channel mapping of the given mix against an expected channel mapping. For reference, see the List Of Channel Labels |
| Comparative Loudness | AQ-123 | Detect mismatch in program loudness across multiple audio tracks. Loudness tolerance, mode standard and dialog gating parameters are available |
| Dolby Atmos Loudness | AQ-124 | Checks that the measured integrated loudness does not exceed the specified maximum value. A value for tolerance can be included. Additionally checks that the measured True Peak loudness does not exceed the specified maxium value. |
| AI Language Detection | AQ-125 | Uses AI to analyze audio and verify it matches the expected language. |
| AI Lip Sync Detection (Tech Preview) | AQ-127 | This test uses AI to analyze video and audio to ascertain whether they are in sync. This tech preview has some limitations, but improvements will be made as we move from tech preview into full release. |
File Quality
Distribution and Broadcast
Tables
MPEG-2 streams, section 8.5 (Table 8-13)
| Level | Profile | ||||
|---|---|---|---|---|---|
| Simple | Main | SNR | Spatial | High | |
| High | 80 | 100 all layers 80 mid+base layer 25 base layer | |||
| High-1440 | 60 | 60 all layers 40 mid+base layer 15 base layer | 80 all layers 60 mid+base layer 20 base layer | ||
| Main | 15 | 15 | 15 both layers 10 base layer | 20 all layers 15 mid+base layer 4 base layer | |
| Low | 4 | 4 both layers 3 base layer |
MPEG-2 streams, section 8.5 (Table 8-14)
| Level | Layer | Profile | ||||
|---|---|---|---|---|---|---|
| Simple | Main | SNR | Spatial | High | ||
| High | Enh.2 Enh.1 Base | 9,781,248 | 12,222,464 9,781,248 3,047,424 | |||
| High-1440 | Enh.2 Enh.1 Base | 7,340,032 | 7,340,032 4,882,432 1,835,008 | 9,781,248 7,340,032 2,441,216 |
List Of Channel Labels
| Channel Label | Short Code |
|---|---|
| Unknown | U |
| Left | L |
| Right | R |
| Center | C |
| Low Frequency Effects | LFE |
| Left Surround | LS |
| Right Surround | RS |
| Left Center | LC |
| Right Center | RC |
| Center Surround | CS |
| Left Side | LSD |
| Right Side | RSD |
| Top Center | TCS |
| Top Front Left | TFL |
| Top Front Center | TFC |
| Top Front Right | TFR |
| Top Back Left | TBL |
| Top Back Center | TBC |
| Top Back Right | TBR |
| Top Side Left | TSL |
| Top Side Right | TSR |
| Left Wide | LW |
| Right Wide | RW |
| Low Frequency Effects 2 | LFE2 |
| Left Rear Surround | LRS |
| Right Rear Surround | RRS |
| Left Total | LT |
| Right Total | RT |
| Mono | M |