Rec. ITU-T H.265.1 (10/2014) 3
6.5 Procedure to test decoder conformance
6.5.1 Conformance bitstreams
A bitstream has values of general_profile_idc, general_tier_flag, and general_level_idc corresponding to a set of specified
constraints on a bitstream for which a decoder conforming to a specified profile, tier, and level is required in Annex A of
Rec. ITU-T H.265 | ISO/IEC 23008-2 to properly perform the decoding process.
6.5.2 Contents of the bitstream file
The conformance bitstreams are included in this Recommendation | International Standard as an electronic attachment.
The following information is included in a single zipped file for each such bitstream.
– bitstream;
– decoded pictures or hashes of decoded pictures (may not be present);
– short description of the bitstream;
– trace file (results while decoding the bitstream, in ASCII format).
In cases where the decoded pictures or hashes of decoded pictures are not available, the reference software decoder shall
be used to generate the necessary reference decoded pictures from the bitstream.
6.5.3 Requirements on output of the decoding process and timing
Two classes of decoder conformance are specified:
– output order conformance; and
– output timing conformance.
The output of the decoding process is specified in clause 8 and Annex C of Rec. ITU-T H.265 | ISO/IEC 23008-2.
For output order conformance, it is a requirement that all of the decoded pictures specified for output in Annex C of
Rec. ITU-T H.265 | ISO/IEC 23008-2 shall be output by a conforming decoder in the specified order and that the values
of the decoded samples in all of the pictures that are output shall be (exactly equal to) the values specified in clause 8 of
Rec. ITU-T H.265 | ISO/IEC 23008-2.
For output timing conformance, it is a requirement that a conforming decoder shall also output the decoded samples at
the rates and times specified in Annex C of Rec. ITU-T H.265 | ISO/IEC 23008-2.
The display process, which ordinarily follows the output of the decoding process, is outside the scope of this
Recommendation | International Standard.
6.5.4 Recommendations (informative)
This clause does not form an integral part of this Recommendation | International Standard.
In addition to the requirements, it is desirable that conforming decoders implement various informative recommendations
specified in Rec. ITU-T H.265 | ISO/IEC 23008-2 that are not an integral part of that Recommendation | International
Standard. This clause discusses some of these recommendations.
It is recommended that a conforming decoder be able to resume the decoding process as soon as possible after the loss or
corruption of part of a bitstream. In most cases it is possible to resume decoding at the next start code or slice header. It
is recommended that a conforming decoder be able to perform concealment for the coding tree blocks or video packets
for which all the coded data has not been received.
6.5.5 Static tests for output order conformance
Static tests of a video decoder require testing of the decoded samples. This clause will explain how this test can be
accomplished when the decoded samples at the output of the decoding process are available. It may not be possible to
perform this type of test with a production decoder (due to the lack of an appropriate accessible interface in the design at
which to perform the test). In that case this test should be performed by the manufacturer during the design and
development phase. Static tests are used for testing the decoding process. The test will check that the values of the samples
decoded by the decoder under test shall be identical to the values of the samples decoded by the reference decoder. When
a hash of the values of the samples of the decoded pictures is attached to the bitstream file, a corresponding hash operation
performed on the values of the samples of the decoded pictures produced by the decoder under test shall produce the same
results.