The CableLabs EBP Conformance Test Tool is a command-line executable that ingests MPEG transport streams and tests their compliance with the CableLabs ATS and EBP specifications. The Tool is written in C and has been tested on Linux 64-bit and Cygwin 64-bit. Transport streams can be ingested either as files or as network multicast streams.

The main purpose of the Tool is to verify that the Encoder Boundary Points (EBP's) in separate transport streams are aligned in time. The tool does this by parsing the EBP descriptors (EBP_descriptor) in the PMT and EBP structures (EBP_info()) in each transport stream, and then comparing the EBP PTS values across the different streams to validate that they are the same. Myriad other validations are performed, including:

• Validate the groups in the EBP structures.
• Check that audio EBP PTS lags video EBP PTS by no more than 3 seconds.
• Check that multiple EBP structures do not exist in a single PES packet.
• Check that EBP is not present on a TS packet that does not have PUSI bit set.
• Validate that all occurrences of EBP_info and EBP_descriptor parse correctly.
• Verify that the EBP_acquisition_time for a particular EBP_info is the same across transport streams.
• Verify that SCTE35 PTS values are consistent with EBP PTS values; the allowable jitter is configurable in the Tool.
• Verify that the SAP Type of a video frame in a PES packet is consistent with the EBP_SAP_type of an EBP located in the first transport packet of that PES packet.
• Verify that EBP_SAP_type in the EBP_info struct and SAP_type_map of the relevant partition in the EBP_descriptor are consistent.
• If EBP_SAP_flag is not present in the EBP_info struct, verify that the corresponding video frame SAP Type is 1 or 2.
• Verify that the EBP PTS is consistent with the expected location as derived from the EBP_descriptor's EBP_distance and ticks_per_second fields; the allowable jitter in this is configurable in the Tool.

To execute a test, the tool performs the following steps:

1. "Peek" Phase -- An assessment is performed for each transport stream where the program streams and their accompanying EBP parameters are discovered. In the command line options to follow, this is called the “peek” phase. Among the EBP information discovered for each program stream are the EBP partitions present in each stream and whether those partitions are signaled explicitly or implicitly. The Tool handles all possible combinations of explicit/implicit EBP signaling discussed in the ATS specification (REF HERE).

2. Alignment Baseline -- During the "peek" phase, the tool is queueing up EBPs from all input streams. At the conclusion of the peek phase, the tool must locate a starting point in the queues in which all EBPs are aligned. To do this, the queue with the latest EBP PTS at its head becomes the baseline. All other queues are trimmed until they all begin with the same PTS. In situtations where the streams do not have aligned EBPs, the test may fail at this very early step.

3. Test -- At this point, the Tool begins the actual test on the transport streams. Multiple ingest threads, one per transport stream, are launched so that the test is performed in real-time. As the ingest threads find EBP’s, they hand off the EBP’s to analysis threads that do the comparison across transport streams. A summary result report is printed either at the end of the test (in the case of file-base transport streams), or at the request of the user (in the case of multicast transport streams).

The Tool ingests transport streams in two ways: as files, and as network multicast streams. For the file case, the command-line syntax is:

ATSTestApp –f [options] <input file 1> <input file 2> ... <input file N>

where the available options are:

    -p:
    “peek” mode -- only perform initial diagnosis of stream (elementary streams,
    EBP descriptor info, etc); does not perform EBP validation.

The ATSTestApp then runs until the contents of all the files have been analyzed. A log (with a default name EBPTestLog.txt) is written, at the end of which is a pass/fail report on the findings. The log also contains detailed information on the EBP PTS’s found as well as on any errors encountered.

For the network multicast ingest case, the command-line syntax is:

ATSTestApp –m [options] [<source1>@]<ip1>:<port1>...[<sourceN>@]<ipN>:<portN>

where the available options are:

    -p:
    “peek” mode: only perform initial diagnosis of stream (elementary streams,
    EBP descriptor info, etc); does not perform EBP validation.

    -d:
    save all transport stream to files: files will be of the form
    EBPStreamDump_<IP>.<port>.ts

The ATSTestApp opens sockets to receive the streams, and performs the “peek” analysis. After this is complete, the actual test begins. At this time the user is presented with a menu of options. Note that if the peek phase is not completed, this menu will not appear.

          x then return to exit
          r then return to create report
          c then return to clear report data
          s then return to see a status of the incoming streams

• r -- creates a report detailing the pass/fail status as well as details of any errors found.
• c -- deletes all test results and restarts the test
• s -- shows the status of the various internal queues to check that the Tool is keeping up with the data being ingested.

The Tool has various configurable properties contained in the file ATSTestApp.props. The default props file is:

// logLevel: 1 ERROR, 2 WARNING, 3 INFO, 4 DEBUG
logLevel = 3

// enter log path here then uncomment – default is EBPTestLog.txt
//logFilePath = 

// amount of time spent searching for EBP structs at start of test in
// the case where EBP descriptor is not present
ebpPrereadSearchTimeMsecs = 10000

// allowed time difference between expected EBP location (from EBP 
// descriptor, if present) actual EBP location
ebpAllowedPTSJitterSecs = 0.5

// allowed time difference between expected EBP location (from SCTE35, 
// if present)and actual EBP location
ebpSCTE35PTSJitterSecs = 0.5

// for multicast case, size of UDP receive buffer
socketRcvBufferSz = 2000000

// size of buffer holding transport stream data waiting to be 
// processed. This needs to be a bit larger than the 
// ebpPrereadSearchTime above, since all of the data is cached here 
// while it is analyzed.
ingestCircularBufferSz = 1880000

The Tool can be built on either Linux or Windows (via Cygwin). To perform a build, go to the top-level directory and type “make”. The executable for the Tool is named ATSTestApp.exe, and resides in the atstest subfolder.

The subfolders contain source code for the various components:

• atstest: top-level code and test threading and logic
• tslib: transport packet parsing code
• logging: logging implementation
• libstructures: data structure implementation
• h264bitstream: h264 parsing code
• common: misc code
• atsstreamapp: test utility to produce multicast streams from transport stream files.

The best approach for debugging issues is to open the log file (named by default EBPTestLog.txt, or alternatively specified in the props file), and search for ERROR entries.