User manual

Encoding Parameters
Harmony 2ES and 4ES 31
6. Although the Harmony can transcode, i.e convert
NTSC to PAL and vice versa real-time, it is
recommended to encode to the video standard (NTSC
or PAL) that the Harmony is set to display.
7. When encoding files, annotate and store notes on the
audio levels of both the source tape and input settings
of the encoder. This permits verifying the audio levels
of later encoding sessions.
8. MPEG files are constructed from i.e. multiplexed audio
and video streams. If possible, the length of the video
and audio stream segments within the MPEG files
should be identical. Ending the audio segment at a .5
second interval, i.e., at an “I-frame”, ensures identical
stream lengths and results in smooth and seamless
looping playback.
9. It is recommended that SMPTE tracks should be
encoded as hot, at approximately +6db.
This adjustment compensates for some SMPTE
information that may be lost during compression.
Sample testing should be done with all SMPTE tracks
because not all encoders respond in the same way.
10. For reference and calibration, encode into the MPEG
files the standard color bars and audio test tones along
with the content or source files. These encoded display
test and audio tuning files should be separate files, not
headers or footers of the presentation.
Variations in MPEG Encoding
Even when encoding is done at the same production facility,
variances between sessions may occur and once MPEGs are
encoded, the audio level of a file cannot be changed unless the file is
re-encoded or a new audio track is mixed.
Thus, it is desirable to maintain a baseline audio level across all files
of a presentation whether at single or multiple locations. If no encod-
ing notes or data are available from previously encoded files, com-
pare the files. When possible, measure the audio levels of the source
tapes and of the encoded files. At a minimum, listen to and compare
the files.