22 October 2026

Cinnafilm Tachyon Frame Rate Conversion

Introduced support for Cinnafilm's Tachyon motion-compensated frame rate conversion, telecine (pulldown) handling, and Dark Energy image restoration.

Set the video settings parameter framerate_method to tachyon to process the output with Tachyon,
and fine-tune the engine with the optional tachyon_parameters group.

See details on Tachyon settings page.

<?xml version="1.0"?>
<query>
    <userid>[UserID]</userid> <!-- required -->
    <userkey>[UserKey]</userkey> <!-- required -->
    <action>[Action]</action> <!-- required -->
    <source>[SourceFile]</source> <!-- required -->
    <format>
        <output>[OutputFormat]</output> <!-- required-->
        <framerate>[FrameRate]</framerate>
        <framerate_method>tachyon</framerate_method>
        <tachyon_parameters>
            <!-- see Tachyon/Dark Energy filter parameters on Tachyon settings page -->
        </tachyon_parameters>
    </format>
</query>

{
  "query": {
    "userid": "[UserID]", // required
    "userkey": "[UserKey]", // required
    "action": "[Action]", // required
    "source": "[SourceFile]", // required
    "format": {
      "output": "[OutputFormat]",
      "framerate": "[FrameRate]",
      "framerate_method": "tachyon",
      "tachyon_parameters": {
        // see Tachyon / Dark Energy filter parameters on Tachyon settings page
      }
    }
  }
}

See the full list of Tachyon and Dark Energy filter parameters on the Tachyon settings page.

Frame offset for closed captions

frame_offset option to shift the closed captions time by a number of frames

The framerate option is now also used to convert frame_offset to seconds, and accepts fraction values (e.g. 30000/1001).

<?xml version="1.0"?>
<query>
    <userid>[UserID]</userid> <!-- required -->
    <userkey>[UserKey]</userkey> <!-- required -->
    <action>[Action]</action> <!-- required -->
    <source>[SourceFile]</source> <!-- required -->
    <format>
        <output>closed_captions</output> <!-- required-->
        <type>[srt|scc|webvtt|dfxp|ttml|mcc|stl]</type>
        <frame_offset>[FRAME_OFFSET]</frame_offset>
        <source_framerate>[Frame rate value]</source_framerate>
        <framerate>[Frame rate value]</framerate>
    </format>
</query>

{
  "query": {
    "userid": "[UserID]", // required
    "userkey": "[UserKey]", // required
    "action": "[Action]", // required
    "source": "[SourceFile]", // required
    "format": {
      "output": "closed_captions",
      "type": "[srt|scc|webvtt|dfxp|ttml|mcc|stl]",
      "frame_offset": "[FRAME_OFFSET]",
      "source_framerate": "[Frame rate value]",
      "framerate": "[Frame rate value]"
    }
  }
}

🚧

A framerate is required to apply frame_offset

The offset in frames is converted to seconds with the value, which must be set whenever <frame_offset /> is used. The source frame rate and the output format defaults are not used to interpret it, so requests specifying <frame_offset /> without are rejected for every output format (SCC, MCC and STL included).

An SCC source holds its timings as frame counts, and so does a video the captions are extracted from
(it is read as an MCC), so reading one needs a framerate as well — and one value cannot be both that and
the rate the offset is counted in. is the offset's rate, so such a source is read with
<source_framerate />, or with the rate it states itself (an MCC names it in its header), or failing both
with the rate its format is conventionally in, 29.97 for an SCC. Set <source_framerate /> when the source
is not at that rate, a 25 fps SCC for instance. Other sources need none: SubRip and WebVTT hold time,
EBU STL and TTML carry their own framerate.

If you already pass to say what rate your SCC is in, move that value to
<source_framerate /> when you add an offset in frames — is the offset's rate from
then on, and the source would otherwise be read at 29.97.

The closed captions offset options are mutually exclusive: a request specifying <frame_offset /> together with <time_offset /> or <set_first_timecode /> is rejected. An empty value is not a request — the unused elements can be sent empty.

The captions offset options apply to generated captions as well: the result of a speech to text () or a request is shifted the same way.

Set the first closed captions timecode

set_first_timecode option to move the first cue of the converted closed
captions to the requested time — all the other cues are shifted by the same offset, so the captions keep their
relative timings.

<?xml version="1.0"?>
<query>
    <userid>[UserID]</userid> <!-- required -->
    <userkey>[UserKey]</userkey> <!-- required -->
    <action>[Action]</action> <!-- required -->
    <source>[SourceFile]</source> <!-- required -->
    <format>
        <output>closed_captions</output> <!-- required-->
        <type>[srt|scc|webvtt|dfxp|ttml|mcc|stl]</type>
        <set_first_timecode>[FIRST_TIMECODE]</set_first_timecode>
        <source_framerate>[Frame rate value]</source_framerate>
        <framerate>[Frame rate value]</framerate>
    </format>
</query>

{
  "query": {
    "userid": "[UserID]", // required
    "userkey": "[UserKey]", // required
    "action": "[Action]", // required
    "source": "[SourceFile]", // required
    "format": {
      "output": "closed_captions",
      "type": "[srt|scc|webvtt|dfxp|ttml|mcc|stl]",
      "set_first_timecode": "[FIRST_TIMECODE]",
      "source_framerate": "[Frame rate value]",
      "framerate": "[Frame rate value]"
    }
  }
}

The value is a HH:MM:SS:FF timecode (HH:MM:SS;FF for drop frame), a HH:MM:SS.mmm timestamp or a plain
number of seconds. For example, captions starting at 00:00:01.500 requested with
<set_first_timecode>01:00:00.000</set_first_timecode> are shifted by +3598.5 seconds.

For an SCC or MCC source the first cue is the moment the first caption is displayed, not the
moment its data starts: a line of an SCC holds the caption data, which a pop on caption shows only
when its end of caption code arrives, and a line can carry no caption at all (XDS packets and null
padding are lines too). The source is decoded exactly the way a SubRip conversion of it is decoded.
Set a to be sure of the measurement: without one the source is read with the source
video's frame rate, or with the output format's default framerate, which is 25 fps for an STL output
even when the source is an SCC.

Mind the drop frame separator for the NTSC framerates: at 29.97 fps 01:00:00:00 (non drop) is 3603.6
seconds while 01:00:00;00 (drop frame) is 3600 seconds — 3.6 seconds apart.

🚧

A framerate is required to read a timecode

A HH:MM:SS:FF value is converted to seconds with the value, which must be set whenever the timecode form is used. The source frame rate and the output format defaults are not used to read it, so requests specifying a HH:MM:SS:FF timecode without are rejected for every output format (SCC, MCC and STL included). The <set_first_timecode /> values that need no framerate (HH:MM:SS.mmm or seconds) are always accepted.

The first cue has to be read from the source to calculate the offset, so a request asking for
<set_first_timecode /> on captions whose cues can't be read fails instead of returning the original
timings. An empty captions source is the exception: there is nothing to shift and the conversion proceeds.

An SCC source holds its timings as frame counts, and so does a video the captions are extracted from
(it is read as an MCC), so reading one needs a framerate as well — and one value cannot be both that and
the rate the offset is counted in. is the offset's rate, so such a source is read with
<source_framerate />, or with the rate it states itself (an MCC names it in its header), or failing both
with the rate its format is conventionally in, 29.97 for an SCC. Set <source_framerate /> when the source
is not at that rate, a 25 fps SCC for instance. Other sources need none: SubRip and WebVTT hold time,
EBU STL and TTML carry their own framerate.

If you already pass to say what rate your SCC is in, move that value to
<source_framerate /> when you add an offset in frames — is the offset's rate from
then on, and the source would otherwise be read at 29.97.

The closed captions offset options are mutually exclusive: a request specifying <set_first_timecode /> together with <time_offset /> or <frame_offset /> is rejected. An empty value is not a request — the unused elements can be sent empty.

The captions offset options apply to generated captions as well: the result of a speech to text () or a request is shifted the same way.

H.264 encoder defaults and automatic level

Encoder defaults

New use_defaults video codec parameter for libx264 codec selects the defaults for the parameters under video_codec_parameters that are not set in the request: edc applies the EDC default values listed in the documentation, codec leaves them unset, so the x264 encoder uses its defaults, except the profile and preset, which follow the format-level settings.

<?xml version="1.0"?>
<query>
    <userid>[UserID]</userid> <!-- required -->
    <userkey>[UserKey]</userkey> <!-- required -->
    <action>[Action]</action> <!-- required -->
    <source>[SourceFile]</source> <!-- required -->
    <format>
        <output>[OutputFormat]</output> <!-- required -->
        <video_codec>libx264</video_codec>
        <profile>[high|main|baseline]</profile>
        <video_codec_parameters>
            <use_defaults>[edc|codec]</use_defaults>
            <!-- video_codec parameters -->
        </video_codec_parameters>
        <!-- format parameters -->
    </format>
</query>

{
  "query": {
    "userid": "[UserID]", // required
    "userkey": "[UserKey]", // required
    "action": "[Action]", // required
    "source": "[SourceFile]", // required
    "format": {
      "output": "[OutputFormat]", // required
      "video_codec": "libx264",
      "profile": "[high|main|baseline]",
      "video_codec_parameters": {
        "use_defaults": "[edc|codec]"
        // video_codec parameters
      },
      // format parameters
    }
  }
}

Automatic level

Updated level video codec parameter of libx264 to accept auto: the encoder chooses the lowest level that fits the output frame size, frame rate and bitrate.

<video_codec_parameters>
    <level>auto</level>
</video_codec_parameters>

{
  "video_codec_parameters": {
    "level": "auto"
  }
}