Ardour supports three common timecode formats:
<abbr title="Linear/Longitudinal Time Code"><dfn>LTC</dfn></abbr>,
<abbr title="MIDI Time Code"><dfn>MTC</dfn></abbr>, and
- <dfn>MIDI Clock</dfn>, as well as
+ <dfn>MIDI Clock</dfn>, as well as
<dfn>JACK-transport</dfn>, a JACK-specific timecode implementation.
</p>
<p>
- Ardour can generate timecode and thus act as timecode <dfn>master</dfn>,
- providing timecode information to other applications. Ardour can also be
- <dfn>slaved</dfn> to some external source in which case the playhead
- follows the incoming timecode.<br />
- Combining the timecode slave and generator modes, Ardour can also
+ Ardour can generate timecode and thus act as timecode <dfn>master</dfn>,
+ providing timecode information to other applications. Ardour can also be
+ <dfn>slaved</dfn> to some external source in which case the playhead
+ follows the incoming timecode.<br>
+ Combining the timecode slave and generator modes, Ardour can also
<dfn>translate</dfn> timecode. e.g create LTC timecode from incoming MTC.
</p>
<h2>Ardour Timecode Configuration</h2>
<p>
- Each Ardour session has a specific timecode frames-per-second setting which
+ Each Ardour session has a specific timecode frames-per-second setting which
is configured in <kbd class="menu">session > properties >
- timecode</kbd>. The selected timecode affects the timecoderuler in the main
+ timecode</kbd>. The selected timecode affects the timecode ruler in the main
window as well as the clock itself.
</p>
<p>
- Note that some timecode formats do not support all of Ardour's available
+ Note that some timecode formats do not support all of Ardour's available
fps settings. MTC is limited to 24, 25, 29.97 and 30 fps.
</p>
<p>
The video pull-up modes change the effective samplerate of Ardour to allow
- for changing a film soundtrack from one frame rate to another. The concept is
- beyond the scope of this manual, but Wikipedia's entry on
- <a href="http://en.wikipedia.org/wiki/Telecine">Telecine</a>
- may get you started.
+ for changing a film soundtrack from one frame rate to another. The concept is
+ beyond the scope of this manual, but Wikipedia's entry on
+ <a href="http://en.wikipedia.org/wiki/Telecine">Telecine</a>
+ may be a good start.
</p>
<h2>Ardour Timecode Generator Configuration</h2>
<p>
- This is pretty straightforward: simply turn it on. The MTC and MIDI-Clock
+ This is pretty straightforward: simply turn it on. The MTC and MIDI-Clock
generator do not have any options. The LTC generator has a configurable
- output level. JACK-transport cannot be <em>generated</em>. Jack itself is
- always synced to its own cycle and cannot do varispeed — it will
+ output level. JACK-transport cannot be <em>generated</em>. Jack itself is
+ always synced to its own cycle and cannot do varispeed—it will
always be synced to a hardware clock or another JACK master.
</p>
<p>
- The relevant settings for timecode generator can be found in
+ The relevant settings for timecode generator can be found in
<kbd class="menu">Edit > Preferences > MIDI Preferences</kbd> (for MTC,
MC) and
<kbd class="menu">Edit > Preferences > Transport Preferences</kbd>
</p>
<p>
- The timecode is sent to jack-ports <code>ardour:MTC out</code>,
- <code>ardour:MIDI clock out</code> and <code>ardour:LTC-out</code>. Multiple
+ The timecode is sent to jack-ports <code>ardour:MTC out</code>,
+ <code>ardour:MIDI clock out</code> and <code>ardour:LTC-out</code>. Multiple
generators can be active simultaneously.
</p>
<p class="note">
- Note that, as of Jan 2014, only the LTC generator supports latency
- compensation. This is due to the fact the Ardour MIDI ports are not
+ Note that, as of Jan 2014, only the LTC generator supports latency
+ compensation. This is due to the fact the Ardour MIDI ports are not
yet latency compensated.
</p>
<p>
- In <kbd class="menu">Session > Properties</kbd>, it is possible to
- define an offset between Ardour's internal time and the timecode sent.
+ In <kbd class="menu">Session > Properties</kbd>, it is possible to
+ define an offset between Ardour's internal time and the timecode sent.
Currently only the LTC generator honors this offset.
</p>
<p>
- Both LTC and MTC are limited to 30 fps. Using frame rates larger
- than that will disable the generator. In both cases also only 24, 25,
- 29.97df (drop-frame) and 30 fps are well defined by specifications (such as
+ Both LTC and MTC are limited to 30 fps. Using frame rates larger
+ than that will disable the generator. In both cases also only 24, 25,
+ 29.97df (drop-frame) and 30 fps are well defined by specifications (such as
SMPTE-12M, EU and the MIDI standard).
</p>
<h3>MTC Generator</h3>
<p>
- The <dfn>MTC generator</dfn> has no options. Ardour sends full MTC
- frames whenever the transport is relocated or changes state (start/stop).
- MTC <dfn>quarter frames</dfn> are sent when the transport is rolling and
+ The <dfn>MTC generator</dfn> has no options. Ardour sends full MTC
+ frames whenever the transport is relocated or changes state (start/stop).
+ MTC <dfn>quarter frames</dfn> are sent when the transport is rolling and
the transport speed is within 93% and 107%.
</p>
<h3>LTC Generator</h3>
<p>
- The level of the <dfn>LTC generator</dfn> output signal can be configured
- in in the <kbd class="menu">Preferences > Transport</kbd> dialog. By
- default it is set to -18 dBFS, which corresponds to 0dBu in an EBU
+ The level of the <dfn>LTC generator</dfn> output signal can be configured
+ in in the <kbd class="menu">Preferences > Transport</kbd> dialog. By
+ default it is set to -18 dBFS, which corresponds to 0dBu in an EBU
calibrated system.
</p>
<p>
- The LTC generator has an additional option to keep sending timecode even
- when the transport is stopped. This mode is intended to drive analog tape
+ The LTC generator has an additional option to keep sending timecode even
+ when the transport is stopped. This mode is intended to drive analog tape
machines which unspool the tape if no LTC timecode is received.
</p>
<p>
- LTC is send regardless of Ardour's transport speed. It is accurately
- generated even for very slow speeds (<5%) and only limited by the
- soundcard's sampling-rate and filter (see
+ LTC is sent regardless of Ardour's transport speed. It is accurately
+ generated even for very slow speeds (<5%) and only limited by the
+ soundcard's sampling-rate and filter (see
<a
- href="http://en.wikipedia.org/wiki/Gibbs_phenomenon#Signal_processing_explanation">Gibbs phenomenon</a>)
+ href="http://en.wikipedia.org/wiki/Gibbs_phenomenon#Signal_processing_explanation">Gibbs phenomenon</a>)
for high speeds.
</p>
<h2>Ardour Slave Configuration</h2>
-<p>
- The timecode source can be switched with the button just right of
+<p>
+ The timecode source can be switched with the button just right of
Ardour's main clock. By default it is set to <kbd
- class="menu">Internal</kbd> in which case Ardour will ignore any external
- timecode. The button allows to toggle between Internal and the configured
- timecode source which is chosen in <kbd class="menu">Edit > Preferences
+ class="menu">Internal</kbd> in which case Ardour will ignore any external
+ timecode. The button allows to toggle between Internal and the configured
+ timecode source which is chosen in <kbd class="menu">Edit > Preferences
> Transport</kbd>.
</p>
<p>
- When Ardour is <dfn>chasing</dfn> (synchronizing to) an external timecode
+ When Ardour is <dfn>chasing</dfn> (synchronizing to) an external timecode
source, the following cases need to be distinguished:
</p>
<ol>
<h3>Frames-per-second</h3>
<p>
- If the frames-per-second do not match, Ardour can either re-calculate
+ If the frames-per-second do not match, Ardour can either re-calculate
and map the frames, or the configured FPS (<kbd class="menu">Session >
- Properties</kbd>) can be changed automatically while the slave is active.
- The behavior is configured with the checkbox <kbd class="option">Edit
- > Preferences > Transport > Match session video frame rate to
+ Properties</kbd>) can be changed automatically while the slave is active.
+ The behavior is configured with the checkbox <kbd class="option">Edit
+ > Preferences > Transport > Match session video frame rate to
external timecode</kbd>.
</p>
<p>
- When enabled, the session video frame rate will be changed to match that
- of the selected external timecode source. When disabled, the session video
- frame rate will not be changed to match that of the selected external
- timecode source. Instead the frame rate indication in the main clock will
- flash red, and Ardour will convert between the external timecode standard
+ When enabled, the session video frame rate will be changed to match that
+ of the selected external timecode source. When disabled, the session video
+ frame rate will not be changed to match that of the selected external
+ timecode source. Instead the frame rate indication in the main clock will
+ flash red, and Ardour will convert between the external timecode standard
and the session standard.
</p>
<p class="warning">
- 29.97 drop-frame timecode is another corner case. While the SMPTE 12M-1999
- specifies 29.97df as 30000/1001 frames per second, not all hardware devices
- follow that standard. The checkbox
- <kbd class="option">Lock to 29.9700 fps instead of 30000/1001</kbd> allows
- to use a compatibility mode for those devices.<br />
- When enabled, the external timecode source is assumed to use 29.970000 fps
- instead of 30000/1001. SMPTE 12M-1999 specifies 29.97df as 30000/1001. The
- <abbr title="specification">spec</abbr> further mentions that drop-frame
- timecode has an accumulated error of -86 ms over a 24-hour period.
- Drop-frame timecode would compensate exactly for a NTSC color frame rate
- of 30 * 0.9990 (ie 29.970000). That is <em>not</em> the actual rate. However,
- some vendors use that rate — despite it being against the specs
- — because the variant of using exactly 29.97 fps yields zero timecode
- drift.
+ 29.97 drop-frame timecode is another corner case. While the SMPTE 12M-1999
+ specifies 29.97df as 30000/1001 frames per second, not all hardware devices
+ follow that standard. The checkbox
+ <kbd class="option">Lock to 29.9700 fps instead of 30000/1001</kbd> allows
+ to use a compatibility mode for those devices.<br>
+ When enabled, the external timecode source is assumed to use 29.970000 fps
+ instead of 30000/1001. SMPTE 12M-1999 specifies 29.97df as 30000/1001. The
+ <abbr title="specification">spec</abbr> further mentions that drop-frame
+ timecode has an accumulated error of -86 ms over a 24-hour period.
+ Drop-frame timecode would compensate exactly for a NTSC color frame rate
+ of 30 * 0.9990 (ie 29.970000). That is <em>not</em> the actual rate. However,
+ some vendors use that rate—despite it being against the
+ specs—because the variant of using exactly 29.97 fps yields zero
+ timecode drift.
</p>
<h3>Clock Sync Lock</h3>
<p>
- As described in the
- <a href="http://manual.ardour.org/synchronization/on-clock-and-time/">On Clock and Time</a>
- chapter, timecode and clock are independent. If the external timecode
- source is not in sample-sync with the audio hardware (and JACK), Ardour
+ As described in the
+ <a href="@@on-clock-and-time">On Clock and Time</a>
+ chapter, timecode and clock are independent. If the external timecode
+ source is not in sample-sync with the audio hardware (and JACK), Ardour
needs to run at varispeed to adjust for the discrepancy.
</p>
<p>
- The checkbox <kbd class="option">External timecode is sync locked</kbd>
- allows to select the behavior according to your setup. When enabled, it
- indicates that the selected external timecode source shares sync (Black
+ The checkbox <kbd class="option">External timecode is sync locked</kbd>
+ allows to select the behavior according to the setup. When enabled, it
+ indicates that the selected external timecode source shares sync (Black
& Burst, Wordclock, etc) with the audio interface.
</p>
<p>
- In other words: if enabled, Ardour will only perform initial
- synchronization and keep playing at speed 1.0 instead of vari-speed
+ In other words: if enabled, Ardour will only perform initial
+ synchronization and keep playing at speed 1.0 instead of vari-speed
adjusting to compensate for drift.
</p>
<p class="note">
- Note that vari-speed is unavailable when recording in Ardour, and all
- tracking happens at speed 1.0. So if you want to record in sync with
+ Note that vari-speed is unavailable when recording in Ardour, and all
+ tracking happens at speed 1.0. So in order to record in sync with
external timecode it must be sample-locked or it will drift over time.
</p>
<h3>MIDI Clock</h3>
<p>
- <dfn>MIDI Clock</dfn> is not a timecode format but tempo-based time. The
- absolute reference point is expressed as beats-per-minute and Bar, Beat
- and Tick. There is no concept of sample-locking for MIDI clock signals.
+ <dfn>MIDI Clock</dfn> is not a timecode format but tempo-based time. The
+ absolute reference point is expressed as beats-per-minute and Bar, Beat
+ and Tick. There is no concept of sample-locking for MIDI clock signals.
Ardour will vari-speed if necessary to chase the incoming signal.
</p>
<p>
- Note that the MIDI Clock source must be connected to the
+ Note that the MIDI Clock source must be connected to the
<code>ardour:MIDI clock in</code> port.
</p>
-<h3>LTC - Linear Timecode</h3>
+<h3>LTC—Linear Timecode</h3>
<p>
- The <dfn>LTC</dfn> slave decodes an incoming LTC signal on a JACK audio
+ The <dfn>LTC</dfn> slave decodes an incoming LTC signal on a JACK audio
port. It will auto-detect the frame rate and start locking to the signal
once two consecutive LTC frames have been received.
</p>
<p>
- The incoming timecode signal needs to arrive at the
- <code>ardour:LTC-in</code> port. Port-connections are restored for each
- session and the preference dialog offers an option to select it for all
+ The incoming timecode signal needs to arrive at the
+ <code>ardour:LTC-in</code> port. Port-connections are restored for each
+ session and the preference dialog offers an option to select it for all
sessions.
</p>
<p>
- Ardour's transport is aligned to LTC-frame start/end positions according
- to the SMPTE 12M-1999 specification, which means that the first bit of an
- LTC-Frame is aligned to different Lines of a Video-Frame, depending on the
- TV standard used. Only for Film (24fps) does the LTC-Frame directly match
+ Ardour's transport is aligned to LTC-frame start/end positions according
+ to the SMPTE 12M-1999 specification, which means that the first bit of an
+ LTC-Frame is aligned to different Lines of a Video-Frame, depending on the
+ TV standard used. Only for Film (24fps) does the LTC-Frame directly match
the video Frame boundaries.
</p>
-<img src="/images/ltc-transport-alignment.png" title="LTC frame alignment" alt="LTC frame alignment"/>
-<p><em>Figure: LTC frame alignment for the 525/60 TV standard</em></p>
+<figure class="center">
+ <img src="/images/ltc-transport-alignment.png" alt="LTC frame alignment">
+ <figcaption>
+ LTC frame alignment for the 525/60 TV standard
+ </figcaption>
+</figure>
<p>
- Ardour supports vari-speed and backwards playback but will only follow
- speed changes if the <kbd class="optoff">sync locked</kbd> option is
+ Ardour supports vari-speed and backwards playback but will only follow
+ speed changes if the <kbd class="optoff">sync locked</kbd> option is
disabled.
</p>
<p>
- While Ardour is chasing LTC, the main transport clock will display the
- received Timecode as well as the delta between the incoming signal and
+ While Ardour is chasing LTC, the main transport clock will display the
+ received Timecode as well as the delta between the incoming signal and
Ardour's transport position.
</p>
<p>
- A global offset between incoming timecode and Ardour's transport can be
+ A global offset between incoming timecode and Ardour's transport can be
configured in <kbd class="menu">Session > Properties</kbd>.
</p>
<p>
The user-bits in the received LTC frame are ignored.
</p>
-<h3>MTC - MIDI Timecode</h3>
+<h3>MTC—MIDI Timecode</h3>
<p>
- Ardour's MTC slave parses <dfn>full timecode messages</dfn> as well as
- MTC <dfn>quarter-frame messages</dfn> arriving on the
- <code>ardour:MTC in</code> port. The transport will only start rolling
+ Ardour's MTC slave parses <dfn>full timecode messages</dfn> as well as
+ MTC <dfn>quarter-frame messages</dfn> arriving on the
+ <code>ardour:MTC in</code> port. The transport will only start rolling
once a complete sequence of 8 quarter frames has been received.
</p>
<p>
- Ardour supports vari-speed and backwards playback but will only follow
- MTC speed changes if the <kbd class="optoff">sync locked</kbd> option
+ Ardour supports vari-speed and backwards playback but will only follow
+ MTC speed changes if the <kbd class="optoff">sync locked</kbd> option
is disabled.
</p>
<p>
- When Ardour is chasing MTC, the main transport clock will display the
- received Timecode as well as the delta between the incoming signal and
+ When Ardour is chasing MTC, the main transport clock will display the
+ received Timecode as well as the delta between the incoming signal and
Ardour's transport position.
</p>
<h3>JACK Transport</h3>
<p>
- When slaved to jack, Ardour's transport will be identical to
- JACK-transport. As opposed to other slaves, Ardour can be used to control
- the JACK transport states (stopped/rolling). No port connections need to
+ When slaved to jack, Ardour's transport will be identical to
+ JACK-transport. As opposed to other slaves, Ardour can be used to control
+ the JACK transport states (stopped/rolling). No port connections need to
be made for jack-transport to work.
</p>
<p>
- JACK-transport does not support vari-speed, nor offsets. Ardour does not
+ JACK-transport does not support vari-speed, nor offsets. Ardour does not
chase the timecode but is always in perfect sample-sync with it.
</p>
<p>
- JACK-transport also includes temp-based-time information in Bar:Beats:Ticks
- and beats-per-minute. However, only one JACK application can provide this
- information at a given time. The checkbox
+ JACK-transport also includes temp-based-time information in Bar:Beats:Ticks
+ and beats-per-minute. However, only one JACK application can provide this
+ information at a given time. The checkbox
<kbd class="option">Session > Properties > JACK Time Master</kbd>
configures Ardour to act as translator from timecode to BBT information.
</p>
-
-
projects / ardour-manual / blobdiff