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

Check	Identifier	Description
File Bit Rate	FC-101	Verifies that the calculated bit rate of the file (video audio bit rate/duration) falls within the defined Min/Max parameters.
Duration	FC-102	Checks that the duration of the file (video and audio) falls within the defined Min/Max parameters.
Container Format	FC-103	Verifies the 'wrapper' or container file used to hold the video and/or audio matches the user defined value. Examples would be 'TS' (MPEG-2 Transport Stream), 'MXF', 'MOV' etc.
Size	FC-104	Checks that the total file size falls within the Min/Max parameters.
Container Start Timecode	FC-105	Verifies that the Container Start Timecode matches the user specified value, with an adjustable tolerance. Can also optionally check for drop frame verification.
Container End Timecode	FC-106	Verifies that the Container End Timecode matches the user specified value, with an adjustable tolerance. Can also optionally check for drop frame verification
Compare Stream Lengths	FC-108	Checks whether the audio track is present throughout the duration of the video. An alert is raised if the audio track is shorter than the video track by more than 2 video frames. An alert is also raised if the audio track is found to be significantly longer (more than 2 seconds) than the video.
Container/Header Agrees With Essence	FC-112	This is intended to be a general test to check that parameters which are potentially duplicated between container (systems layer) and essence (elementary stream) are consistent.

Deep MXF Tests

Check	Identifier	Description
Deep MXF Tests	MX-101	A range of in-depth MXF checks, to ensure technical conformance with a variety of MXF constraints.
MXF Operational Pattern	MX-102	Tests the Operational Pattern of an MXF file. Currently only OP-1a and Op-Atom are supported.
AVC SPS/PPS	MX-103	This test ensures that every frame of an AVC stream contains an SPS and PPS header. This is mandated by SMPTE RP2027. This test is only available when the 'Video Codec' test is enabled and set to 'H.264' and the 'Container' test is enabled and set to 'MXF'.

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 for a valid version number for VC-3 streams as per section 7.2.1 of SMPTE ST 2019. The valid version numbers are 01(Compression ID 1235, 1237, 1238, 1241, 1242, 1243, 1244, 1250, 1251, 1252, 1253),02(Compression ID 1256, 1258, 1259, 1260),03(Compression ID 1270, 1271, 1272, 1273, 1274).Values 01 and 02 are HD profile.value 03 is RI profile.
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

Check	Identifier	Description
Closed Caption Presence	CC-101	Checks for the presence or absence of closed captions (C608, C708).
Closed Caption Dropouts	CC-102	Detect and report any closed caption dropouts. Maximum time allowed with no caption data can be specified in seconds or frames.
Teletext Subtitle Presence	CC-103	Checks for the presence or absence of specified teletext page.
Discreet Subtitle Presence	CC-104	Checks for the presence or absence of discrete subtitles.
Discreet Subtitle Dropouts	CC-105	Detect and report any discrete subtitle dropouts. Maximum time allowed with no subtitle data can be specified in seconds or frames. The following STL checks are also available within this test: STL Checks: enable/disable STL checks. Check that Sidecar STL is present: test that an STL that matches the content is present. STL Group: verify the STL Group (for example: service 01 or 00). Only one group can be tested for. STL start timecode check: check that the start timecode of the STL matches the start timecode of the media.

Video Metadata

Check	Identifier	Description
Bit Depth	VM-101	The number of bits per video sample. For cases where luma and chroma sample depths are different, this check will test the luma bit depth.
Video Track ID/PID	VM-102	Checks the ID of the video track within its container format. This is the 'PID' for MPEG-2 Transport Streams, the 'stream_id' for MPEG-2 Program Streams and the 'Track ID' for MOV and MXF files.
Video Bit Rate	VM-103	Check that the bit rate of the video track is within the given range, expressed in Mbit/s.
Codec	VM-105	Tests the format of the video elementary stream.
Color Space Information	VM-106	This tests that the video has certain color space properties (e.g. color primaries, transfer characteristics and matrix coefficients). If a property is not found in the video, a Warning will be generated
Frame Rate	VM-107	Frame rate in video frames per second. "NTSC" denotes a drop frame rate, e.g. "30fps (NTSC)" corresponds to 29.97fps.
Drop Frame	VM-108	Specify whether the file must have drop/non-drop frame timecode.
Frame Size	VM-109	Choose from a selection of standard frame sizes, or specify a Custom frame size (e.g. 2000x1000).
Frame Aspect Ratio	VM-111	Choose from a selection of standard frame aspect ratios, or specify a custom value as an integer or floating point value (e.g. 3 or 1.4).
Pixel Aspect Ratio	VM-112	The aspect ratio of each luminance sample in the coded stream, either as coded directly or implied by the display aspect ratio and frame size.
Chroma Subsampling Format	VM-114	Checks that the chroma subsampling format matches the user specified value. Only applicable for YUV-based video.
Clean Aperture	VM-115	Checks that the Clean Aperture of the video is equal to the Production Aperture. This implies that no cropping of the encoded picture is indicated by the container. This test also verifies that no Clean Aperture offset is indicated. Clean Aperture is a QuickTime concept, thus this test will only be performed on MOV containers.
GOP Length	VM-116	Check the distance between successive I-frames in the encoded video. For example, this distance will be 1 for I-frame only video and 12 for a long GOP sequence coded as 'IBBPBBPBBPBBI'. This test is suitable for GOP coded video, such as MPEG-2 and H.264.
Advanced GOP Length	VM-117	A more thorough GOP test for MPEG-2 and H.264 that can test for a range of GOP lengths, test for open and closed GOPs (MPEG-2 only), and allow special handling of first and last GOPs. The "First GOP" and "Last 2 GOPs" sections, when ticked, enable specific values to be given for the first and last two GOPs. The "Other GOPs" section will apply to any other GOP (possibly including the first and last GOPs if their specific sections are not ticked). The input boxes for I-frame distance and P-frame distance are comma-separated lists of distances or ranges of distances. For example, "12", "1-12", "1,12,15' and "1,12-15" are all valid inputs. The syntax ">5" and "<5" mean "greater than" and "less than" 5 frames, respectively. If the input is empty, then no check is performed (i.e., any distance is valid). It is possible to choose whether the test operates on the coded frame order or the displayed frame order. This distinction is only important when B-frames are present. The test can be configured to either show unique GOP length errors (default) or to show all of them.
Essence Start Timecode	VM-119	Verifies that the Essence Start Timecode matches the user specified input, with an adjustable tolerance. Can also optionally check for drop frame verification. The material package start timecode can also optionally be compared against the GOP timecode.
Essence End Timecode	VM-120	Verifies that the Essence End Timecode matches the user specified input, with an adjustable tolerance. Can also optionally check for drop frame verification.
TV/MPAA Rating	VM-123	Checks the Type 0x05 Content Advisory Packet from the caption data packet in the video stream and compares the results to the value you set in the template.
Video Buffer Size	VM-125	When MPEG-2 is selected, this test checks the VBV buffer size reported in the stream. When AVC/H.264 is selected, this test checks the CPB buffer size reported in the stream. Minimum and Maximum values are specified in KiB (1024 bytes) and either value may be left blank if not required. The 'Video Codec' test must be enabled and set to 'MPEG-2' or 'AVC/H.264' before this test may be used.
MOOV Atom	VM-127	This check is to identify that there is only one MOOV atom in an mov/mp4 file.
Single Sample Description	VM-128	This test looks for the presence of multiple Sample Descriptions in the MOV/MP4 track metadata, which is often an indicator that such incompatible splicing has taken place.

Video Quality

Check	Identifier	Description
Black Frame	VQ-101	Checks for instances of both intentional/unintentional black frames, using a luma level specified in the template (default value varies with different video bit depths). The Percentage of Frame option acts as a tolerance control, and the user can set the maximum number of consecutive black frames that are allowed before an alert is raised. This test also has the ability to check certain parts of the file using the "Layout" controls.
Color Bars	VQ-102	Checks for instances of both intentional/unintentional color bars. The user can specify which type of color bars to search for, and set a tolerance to account for non-standard encoding. This test also has the ability to check certain parts of the file using the "Layout" controls.
Field Order	VQ-103	Tests whether the encoded flag matches the user specified input, and optionally tests that the baseband video also has the desired encoded field order. The user can specify a time threshold to ensure relevant alerts are caught.
Cadence	VQ-104	Checks that the baseband cadence is correct based on the user selected criteria of what is expected in the stream. The user can select from the following expected cadences: Progressive 2:2 (TFF) Top field first interlaced 2:2 (BFF) Bottom field first interlaced 2:3 (TFF) 2:3 cadence mix of progressive and top field first (Prog/Prog/TFF/TFF/Prog) 2:3 (BFF) 2:3 cadence mix of progressive and bottom field first(Prog/Prog/BFF/BFF/Prog) 24 -> 25 fps (TFF) Mix of progressive and top field first used in conversion from 24 fps to 25 fps (12 progressive frames then one TFF) 24 -> 25 fps (BFF) Mix of progressive and bottom field first used in conversion from 24 fps to 25 fps (12 progressive frames then one BFF). The user can optionally look for broken 2:3 cadence; opt to report all detected cadences or check for poor patterns that could cause excessive stutter.
Freeze Frame	VQ-105	Checks for instances of both intentional/unintentional freeze frames. The user can specify the maximum number of allowed consecutive frozen frames before an alert is raised. There is also the ability to ignore black frames, using a user specified luma level (default value varies with different bit depths). This test also has the ability to check certain parts of the file using the "Layout" controls.
HDR Area	VQ-106	This test measures the number of HDR pixels in a PQ or HLG-1000 graded frame. As per ITU-R B.2408-1 recommendations, a pixel with luminance more than 203 nits is considered HDR. An alert is generated when the percentage of HDR pixels in a frame exceeds the Area Threshold and when this continues for the user specified number of measurements.
HDR Change Detection	VQ-107	Checks for changes to the SEI-encoded HDR metadata on a frame-by-frame basis. Any changes to this metadata cause an alert to be raised.
HDR Limit	VQ-108	This test measures how many HDR pixels lie above the brightest two thresholds, and how many lie below the darkest, giving the user a reliable and useful metric as to how much their content lies within "HDR" boundaries.
HDR Measurement	VQ-109	This test measures analyses each decoded frame, in its native bit depth, to calculate the MaxCLL (Maximum Content Light Level) and MaxFALL (Maximum Frame Average Light Level). The measured values are compared against the HDR metadata within the file.
Luma/Chroma Levels	VQ-112	This tests that the luma component (Y) of the YUB signal is within valid limits. The Low Luma Limit and High Luma Limit fields allow for stricter or more lenient rules for when a pixel is considered a violation. The defaults of -1% to 103% comply with EBU r103.
RGB Gamut	VQ-113	This test ensures that the YUV components of the decoded video lie within the legal range given by ITU-R- BT.601-5, 709-5 or 2020-1. The default values of -5% to 105% comply with EBU r103.
Media Offline	VQ-114	Checks for the presence of the "Media Offline" slate, which can be produced by applications such as Adobe Premiere, After Effects, Avid Media Composer or DaVinci Resolve.
PSE Test (Proprietary)	VQ-115	Tests for rapid changes in luminance which could trigger photosensitive epilepsy (PSE). This test is in accordance with ITU-R BT 1702-2 (supporting both SDR and HDR content) but can be switched to be run in accordance with ITU-R BT 1702-1 by choosing "Use Legacy". The test will alert if a sequence has more than three and a half harmful flashed per second. Harmful flashes could be caused by both rapid changes of lighting in a scene, or by rapid editorial cuts that cause the screen to flash.
Video Segment Detection	VQ-116	Detects video segments within the content and reports the start and end timecode of each segment found. This test works by identifying consecutive black frames, and assuming that anything which is not black is an active video segment. The user can request that digital silence is also present during black sections to ensure accuracy of detection.
Single Color Frame	VQ-117	Detects sequences where the entire frame is a single color. This can sometimes occur because of syntax errors, missing codecs, or erroneous media encoding.
TekMOS	VQ-118	TekMOS is a non-referenced perceptual video quality measurement for natural video content. The content is rated on a scale of 0-5, with 5 being the highest quality, in line with the ITU 5-point scale. The Program Threshold computes the percentage of frames within the entire program that fall below the user defined threshold. The short-term threshold searches and reports for short sections of poor video quality, according to a user specified rolling window duration.
Letterbox/Pillarbox	VQ-120	This test is used to detect whether video content has the correct letterboxing (black bars at the top and bottom of the frame). If any content fails the test, then a single error alert is raised for each continuous frame sequence. Changes to letterboxing/pillarboxing are also reported. The user can specify the desired active picture aspect ratio, or a requirement for a specific number of black lines at the edges of the picture. A tolerance can also be set to mitigate false positive alerts, and the black level used to detect the black bars can also be adjusted.
Upconversion Detection	VQ-128	Performs two passes on the key frames for each video stream in the container to determine if they have been upconverted from a lower resolution. A comparison is then made between the original frame to the frame that has passed through the two pass conversion.
Macroblocking	VQ-131	Checks for macroblocking artifacts where the macroblock edge is clearly visible. This test is a subjective measure of video quality where each frame is assigned a quality metric and an alert is raised if the video quality drops below the given threshold.
Corrupt Frame	VQ-133	Checks for corrupt or unexpected frames. Single or double frames which look out of place in a sequence will be found. These could be frames with a significant amount of corruption, or single dark or bright frames could also cause an alert to be raised. Sensitivity: A high sensitivity will find more problems but could also find more 'false positives'. A low sensitivity will only detect more obvious problems.
HardingFPA	VQ-135	Tests for rapid changes in luminance which could trigger photosensitive epilepsy (PSE). This test is in accordance with ITU-R BT 1702-2 (supporting both SDR and HDR content.
Combing Artifacts	VQ-136	Checks for interlacing artifacts which manifest by showing a shift in every other line around motion areas of pictures. These are generally caused by the fields being out of order during ingest, and then being transcoded to a format that loses any reference to the proper field order.

Audio Metadata

Check	Identifier	Description
Bit Depth	AM-101	Verifies that the audio bit depth matches the user specified value.
Codec	AM-102	Checks that the audio codec matches the user specified value(s).
Codec Profile	AM-103	Tests the format of the audio elementary stream.
Sample Rate	AM-104	Ensures that the audio sample rate (KHz) matches the user specified value.
Number of Tracks	AM-105	Checks that the number of audio tracks found matches the user specified value.
Bit Rate	AM-106	Ensures that the audio bit rate (kbps) matches the user specified value.
Dialnorm	AM-107	Verifies that the Dialnorm value matches the user specified range. This test is only relevant to assets containing a Dolby encoded audio stream.
Number of Channels	AM-110	Checks that the number of audio channels found matches the user specified range.
Language ID	AM-111	Checks that the language ID found matches the user specified value.

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.
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, which will measure loudness only when dialog is present.
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 (LUFS)	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. Min Level: Min: The minimum acceptable PPM level. Max: The maximum acceptable PPM level. Mode: M3 and M6 modes determine how much attenuation is made after summing the left and right signals.
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.
Test 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.
Audio Description Track Detection	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.

Distribution and Broadcast

Check	Identifier	Description
Nielsen Watermark Detection	DC-103	Decode an audio stream and report Nielsen watermarks found in the stream. NAES 2: Detects and reports N2 watermarks. NAES 6: Detects and reports Nielsen Watermark TAM** Codes (NW) and Nielsen Watermark Commercial Codes (NWCC). This test will detect watermarks with any specific SID. Multiple SIDs can be entered; they should comma separated (e.g. 45150,61717,6400).
iTunes Compliance	DC-107	Tests several aspects of MOV file atom structure which are relevant for iTunes submission: The video track should have a sample description atom of type 'apch'. The video width and height in the video sample description atom should be either 1920×1080 or 1280×720. The 'vendor' code should be 'appl'. The 'fields' entry should be set to 1 to indicate progressive scan. The 'colr' atom should be present and have the type 'nclc' to indicate non-constant luminance coding. The color primaries, color transfer function and color matrix should all be set to 1. No clean aperture (clap) information should occur after a field (fiel) atom. The edit list (elst atom) for the video track should be exactly 1 entry in size.

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