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Implement "early requests" mode.

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PA_STREAM_EARLY_REQUESTS is a new flag that will modify buffering metric
selection behaviour a bit. This code is good for broken ALSA/OSS clients that
ignore 'readability' on the fds in question and schedule audio via usleep()
instead.
This commit is contained in:
Lennart Poettering 2008-09-03 18:31:46 +02:00
parent 99d5ec6c93
commit 40b66a0be9
4 changed files with 274 additions and 181 deletions
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252
src/pulse/def.h
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@ -96,148 +96,124 @@ typedef enum pa_stream_direction {
/** Some special flags for stream connections. */
typedef enum pa_stream_flags {
PA_STREAM_START_CORKED = 1, /**< Create the stream corked, requiring an explicit pa_stream_cork() call to uncork it. */
PA_STREAM_INTERPOLATE_TIMING = 2, /**< Interpolate the latency for
* this stream. When enabled,
* pa_stream_get_latency() and
* pa_stream_get_time() will try
* to estimate the current
* record/playback time based on
* the local time that passed
* since the last timing info
* update. Using this option
* has the advantage of not
* requiring a whole roundtrip
* when the current
* playback/recording time is
* needed. Consider using this
* option when requesting
* latency information
* frequently. This is
* especially useful on long
* latency network
* connections. It makes a lot
* of sense to combine this
* option with
* PA_STREAM_AUTO_TIMING_UPDATE. */
PA_STREAM_NOT_MONOTONIC = 4, /**< Don't force the time to
* increase monotonically. If
* this option is enabled,
* pa_stream_get_time() will not
* necessarily return always
* monotonically increasing time
* values on each call. This may
* confuse applications which
* cannot deal with time going
* 'backwards', but has the
* advantage that bad transport
* latency estimations that
* caused the time to to jump
* ahead can be corrected
* quickly, without the need to
* wait. (Please note that this
* flag was named
* PA_STREAM_NOT_MONOTONOUS in
* releases prior to 0.9.11. The
* old name is still defined too,
* for compatibility reasons. */
PA_STREAM_AUTO_TIMING_UPDATE = 8, /**< If set timing update requests
* are issued periodically
* automatically. Combined with
* PA_STREAM_INTERPOLATE_TIMING
* you will be able to query the
* current time and latency with
* pa_stream_get_time() and
* pa_stream_get_latency() at
* all times without a packet
* round trip.*/
PA_STREAM_NO_REMAP_CHANNELS = 16, /**< Don't remap channels by
* their name, instead map them
* simply by their
* index. Implies
* PA_STREAM_NO_REMIX_CHANNELS. Only
* supported when the server is
* at least PA 0.9.8. It is
* ignored on older
* servers.\since 0.9.8 */
PA_STREAM_NO_REMIX_CHANNELS = 32, /**< When remapping channels by
* name, don't upmix or downmix
* them to related
* channels. Copy them into
* matching channels of the
* device 1:1. Only supported
* when the server is at least
* PA 0.9.8. It is ignored on
* older servers. \since
* 0.9.8 */
PA_STREAM_FIX_FORMAT = 64, /**< Use the sample format of the
* sink/device this stream is being
* connected to, and possibly ignore
* the format the sample spec contains
* -- but you still have to pass a
* valid value in it as a hint to
* PulseAudio what would suit your
* stream best. If this is used you
* should query the used sample format
* after creating the stream by using
* pa_stream_get_sample_spec(). Also,
* if you specified manual buffer
* metrics it is recommended to update
* them with
* pa_stream_set_buffer_attr() to
* compensate for the changed frame
* sizes. Only supported when the
* server is at least PA 0.9.8. It is
* ignored on older servers. \since
* 0.9.8 */
PA_STREAM_FIX_RATE = 128, /**< Use the sample rate of the sink,
* and possibly ignore the rate the
* sample spec contains. Usage similar
* to PA_STREAM_FIX_FORMAT.Only
* supported when the server is at least
* PA 0.9.8. It is ignored on older
* servers. \since 0.9.8 */
PA_STREAM_START_CORKED = 0x0001U,
/**< Create the stream corked, requiring an explicit
* pa_stream_cork() call to uncork it. */
PA_STREAM_FIX_CHANNELS = 256, /**< Use the number of channels and
* the channel map of the sink, and
* possibly ignore the number of
* channels and the map the sample spec
* and the passed channel map
* contains. Usage similar to
* PA_STREAM_FIX_FORMAT. Only supported
* when the server is at least PA
* 0.9.8. It is ignored on older
* servers. \since 0.9.8 */
PA_STREAM_DONT_MOVE = 512, /**< Don't allow moving of this stream to
* another sink/device. Useful if you use
* any of the PA_STREAM_FIX_ flags and
* want to make sure that resampling
* never takes place -- which might
* happen if the stream is moved to
* another sink/source whith a different
* sample spec/channel map. Only
* supported when the server is at least
* PA 0.9.8. It is ignored on older
* servers. \since 0.9.8 */
PA_STREAM_VARIABLE_RATE = 1024, /**< Allow dynamic changing of the
* sampling rate during playback
* with
* pa_stream_update_sample_rate(). Only
* supported when the server is at
* least PA 0.9.8. It is ignored
* on older servers. \since
* 0.9.8 */
PA_STREAM_PEAK_DETECT = 2048, /**< Find peaks instead of
* resampling. \since 0.9.11 */
PA_STREAM_INTERPOLATE_TIMING = 0x0002U,
/**< Interpolate the latency for this stream. When enabled,
* pa_stream_get_latency() and pa_stream_get_time() will try to
* estimate the current record/playback time based on the local
* time that passed since the last timing info update. Using this
* option has the advantage of not requiring a whole roundtrip
* when the current playback/recording time is needed. Consider
* using this option when requesting latency information
* frequently. This is especially useful on long latency network
* connections. It makes a lot of sense to combine this option
* with PA_STREAM_AUTO_TIMING_UPDATE. */
PA_STREAM_START_MUTED = 4096, /**< Create in muted state. \since 0.9.11 */
PA_STREAM_NOT_MONOTONIC = 0x0004U,
/**< Don't force the time to increase monotonically. If this
* option is enabled, pa_stream_get_time() will not necessarily
* return always monotonically increasing time values on each
* call. This may confuse applications which cannot deal with time
* going 'backwards', but has the advantage that bad transport
* latency estimations that caused the time to to jump ahead can
* be corrected quickly, without the need to wait. (Please note
* that this flag was named PA_STREAM_NOT_MONOTONOUS in releases
* prior to 0.9.11. The old name is still defined too, for
* compatibility reasons. */
PA_STREAM_AUTO_TIMING_UPDATE = 0x0008U,
/**< If set timing update requests are issued periodically
* automatically. Combined with PA_STREAM_INTERPOLATE_TIMING you
* will be able to query the current time and latency with
* pa_stream_get_time() and pa_stream_get_latency() at all times
* without a packet round trip.*/
PA_STREAM_NO_REMAP_CHANNELS = 0x0010U,
/**< Don't remap channels by their name, instead map them simply
* by their index. Implies PA_STREAM_NO_REMIX_CHANNELS. Only
* supported when the server is at least PA 0.9.8. It is ignored
* on older servers.\since 0.9.8 */
PA_STREAM_NO_REMIX_CHANNELS = 0x0020U,
/**< When remapping channels by name, don't upmix or downmix them
* to related channels. Copy them into matching channels of the
* device 1:1. Only supported when the server is at least PA
* 0.9.8. It is ignored on older servers. \since 0.9.8 */
PA_STREAM_FIX_FORMAT = 0x0040U,
/**< Use the sample format of the sink/device this stream is being
* connected to, and possibly ignore the format the sample spec
* contains -- but you still have to pass a valid value in it as a
* hint to PulseAudio what would suit your stream best. If this is
* used you should query the used sample format after creating the
* stream by using pa_stream_get_sample_spec(). Also, if you
* specified manual buffer metrics it is recommended to update
* them with pa_stream_set_buffer_attr() to compensate for the
* changed frame sizes. Only supported when the server is at least
* PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
PA_STREAM_FIX_RATE = 0x0080U,
/**< Use the sample rate of the sink, and possibly ignore the rate
* the sample spec contains. Usage similar to
* PA_STREAM_FIX_FORMAT.Only supported when the server is at least
* PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
PA_STREAM_FIX_CHANNELS = 0x0100,
/**< Use the number of channels and the channel map of the sink,
* and possibly ignore the number of channels and the map the
* sample spec and the passed channel map contains. Usage similar
* to PA_STREAM_FIX_FORMAT. Only supported when the server is at
* least PA 0.9.8. It is ignored on older servers. \since 0.9.8 */
PA_STREAM_DONT_MOVE = 0x0200U,
/**< Don't allow moving of this stream to another
* sink/device. Useful if you use any of the PA_STREAM_FIX_ flags
* and want to make sure that resampling never takes place --
* which might happen if the stream is moved to another
* sink/source whith a different sample spec/channel map. Only
* supported when the server is at least PA 0.9.8. It is ignored
* on older servers. \since 0.9.8 */
PA_STREAM_VARIABLE_RATE = 0x0400U,
/**< Allow dynamic changing of the sampling rate during playback
* with pa_stream_update_sample_rate(). Only supported when the
* server is at least PA 0.9.8. It is ignored on older
* servers. \since 0.9.8 */
PA_STREAM_PEAK_DETECT = 0x0800U,
/**< Find peaks instead of resampling. \since 0.9.11 */
PA_STREAM_START_MUTED = 0x1000U,
/**< Create in muted state. \since 0.9.11 */
PA_STREAM_ADJUST_LATENCY = 0x2000U,
/**< Try to adjust the latency of the sink/source based on the
* requested buffer metrics and adjust buffer metrics
* accordingly. Also see pa_buffer_attr. This option may not be
* specified at the same time as PA_STREAM_EARLY_REQUESTS. \since
* 0.9.11 */
PA_STREAM_EARLY_REQUESTS = 0x4000U
/**< Enable compatibility mode for legacy clients that rely on a
* "classic" hardware device fragment-style playback model. If
* this option is set, the minreq value of the buffer metrics gets
* a new meaning: instead of just specifying that no requests
* asking for less new data than this value will be made to the
* client it will also guarantee that requests are generated as
* early as this limit is reached. This flag should only be set in
* very few situations where compatiblity with a fragment-based
* playback model needs to be kept and the client applications
* cannot deal with data requests that are delayed to the latest
* moment possible. (Usually these are programs that use usleep()
* or a similar call in their playback loops instead of sleeping
* on the device itself.) Also see pa_buffer_attr. This option may
* not be specified at the same time as
* PA_STREAM_ADJUST_LATENCY. \since 0.9.12 */
PA_STREAM_ADJUST_LATENCY = 8192, /**< Try to adjust the latency of
* the sink/source based on the
* requested buffer metrics and
* adjust buffer metrics
* accordingly. See pa_buffer_attr \since 0.9.11 */
} pa_stream_flags_t;
/** \cond fulldocs */