[FFmpeg-devel] [PATCH] swresample: misc. doxy improvements
Timothy Gu
timothygu99 at gmail.com
Tue Jul 8 00:23:49 CEST 2014
Signed-off-by: Timothy Gu <timothygu99 at gmail.com>
---
libswresample/swresample.h | 83 +++++++++++++++++++++++++++++++++++-----------
1 file changed, 64 insertions(+), 19 deletions(-)
diff --git a/libswresample/swresample.h b/libswresample/swresample.h
index 838fb5c..e4bbeba 100644
--- a/libswresample/swresample.h
+++ b/libswresample/swresample.h
@@ -189,6 +189,7 @@ typedef struct SwrContext SwrContext;
* AV_OPT_SEARCH_FAKE_OBJ for examining options.
*
* @see av_opt_find().
+ * @return the AVClass of SwrContext
*/
const AVClass *swr_get_class(void);
@@ -211,6 +212,7 @@ struct SwrContext *swr_alloc(void);
/**
* Initialize context after user parameters have been set.
*
+ * @param[in,out] s Swr context to initialize
* @return AVERROR error code in case of failure.
*/
int swr_init(struct SwrContext *s);
@@ -218,6 +220,8 @@ int swr_init(struct SwrContext *s);
/**
* Check whether an swr context has been initialized or not.
*
+ * @param[in] s Swr context to check
+ * @see swr_init()
* @return positive if it has been initialized, 0 if not initialized
*/
int swr_is_initialized(struct SwrContext *s);
@@ -229,7 +233,7 @@ int swr_is_initialized(struct SwrContext *s);
* other hand, swr_alloc() can use swr_alloc_set_opts() to set the parameters
* on the allocated context.
*
- * @param s Swr context, can be NULL
+ * @param s existing Swr context if available, or NULL if not
* @param out_ch_layout output channel layout (AV_CH_LAYOUT_*)
* @param out_sample_fmt output sample format (AV_SAMPLE_FMT_*).
* @param out_sample_rate output sample rate (frequency in Hz)
@@ -256,6 +260,8 @@ struct SwrContext *swr_alloc_set_opts(struct SwrContext *s,
/**
* Free the given SwrContext and set the pointer to NULL.
+ *
+ * @param[in] s a pointer to a pointer to Swr context
*/
void swr_free(struct SwrContext **s);
@@ -266,6 +272,8 @@ void swr_free(struct SwrContext **s);
* swr_init() can also be used without swr_close().
* This function is mainly provided for simplifying the usecase
* where one tries to support libavresample and libswresample.
+ *
+ * @param[in,out] s Swr context to be closed
*/
void swr_close(struct SwrContext *s);
@@ -301,12 +309,16 @@ int swr_convert(struct SwrContext *s, uint8_t **out, int out_count,
* timestamps are in 1/(in_sample_rate * out_sample_rate) units.
*
* @note There are 2 slightly differently behaving modes.
- * First is when automatic timestamp compensation is not used, (min_compensation >= FLT_MAX)
+ * @li When automatic timestamp compensation is not used, (min_compensation >= FLT_MAX)
* in this case timestamps will be passed through with delays compensated
- * Second is when automatic timestamp compensation is used, (min_compensation < FLT_MAX)
- * in this case the output timestamps will match output sample numbers
- *
- * @param pts timestamp for the next input sample, INT64_MIN if unknown
+ * @li When automatic timestamp compensation is used, (min_compensation < FLT_MAX)
+ * in this case the output timestamps will match output sample numbers.
+ * See ffmpeg-resampler(1) for the two modes of compensation.
+ *
+ * @param s[in] initialized Swr context
+ * @param pts[in] timestamp for the next input sample, INT64_MIN if unknown
+ * @see swr_set_compensation(), swr_drop_output(), and swr_inject_silence() are
+ * function used internally for timestamp compensation.
* @return the output timestamp for the next output sample
*/
int64_t swr_next_pts(struct SwrContext *s, int64_t pts);
@@ -321,17 +333,30 @@ int64_t swr_next_pts(struct SwrContext *s, int64_t pts);
*/
/**
- * Activate resampling compensation.
+ * Activate resampling compensation ("soft" compensation). This function is
+ * internally called when needed in swr_next_pts().
+ *
+ * @param[in,out] s allocated Swr context. If it is not initialized,
+ * or SWR_FLAG_RESAMPLE is not set, swr_init() is
+ * called with the flag set.
+ * @param[in] sample_delta delta in PTS per sample
+ * @param[in] compensation_distance number of samples to compensate for
+ * @return >= 0 on success, AVERROR error codes if:
+ * @li @c s is NULL,
+ * @li @c compensation_distance is less than 0,
+ * @li @c compensation_distance is 0 but sample_delta is not,
+ * @li compensation unsupported by resampler, or
+ * @li swr_init() fails when called.
*/
int swr_set_compensation(struct SwrContext *s, int sample_delta, int compensation_distance);
/**
* Set a customized input channel mapping.
*
- * @param s allocated Swr context, not yet initialized
- * @param channel_map customized input channel mapping (array of channel
- * indexes, -1 for a muted channel)
- * @return AVERROR error code in case of failure.
+ * @param[in,out] s allocated Swr context, not yet initialized
+ * @param[in] channel_map customized input channel mapping (array of channel
+ * indexes, -1 for a muted channel)
+ * @return >= 0 on success, or AVERROR error code in case of failure.
*/
int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map);
@@ -342,7 +367,7 @@ int swr_set_channel_mapping(struct SwrContext *s, const int *channel_map);
* @param matrix remix coefficients; matrix[i + stride * o] is
* the weight of input channel i in output channel o
* @param stride offset between lines of the matrix
- * @return AVERROR error code in case of failure.
+ * @return >= 0 on success, or AVERROR error code in case of failure.
*/
int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride);
@@ -355,11 +380,27 @@ int swr_set_matrix(struct SwrContext *s, const double *matrix, int stride);
/**
* Drops the specified number of output samples.
+ *
+ * This function, along with swr_inject_silence(), is called by swr_next_pts()
+ * if needed for "hard" compensation.
+ *
+ * @param s allocated Swr context
+ * @param count number of samples to be dropped
+ *
+ * @return >= 0 on success, or a negative AVERROR code on failure
*/
int swr_drop_output(struct SwrContext *s, int count);
/**
* Injects the specified number of silence samples.
+ *
+ * This function, along with swr_drop_output(), is called by swr_next_pts()
+ * if needed for "hard" compensation.
+ *
+ * @param s allocated Swr context
+ * @param count number of samples to be dropped
+ *
+ * @return >= 0 on success, or a negative AVERROR code on failure
*/
int swr_inject_silence(struct SwrContext *s, int count);
@@ -375,13 +416,17 @@ int swr_inject_silence(struct SwrContext *s, int count);
* for upsampling and the input sample rate.
*
* @param s swr context
- * @param base timebase in which the returned delay will be
- * if its set to 1 the returned delay is in seconds
- * if its set to 1000 the returned delay is in milli seconds
- * if its set to the input sample rate then the returned delay is in input samples
- * if its set to the output sample rate then the returned delay is in output samples
- * an exact rounding free delay can be found by using LCM(in_sample_rate, out_sample_rate)
- * @returns the delay in 1/base units.
+ * @param base timebase in which the returned delay will be:
+ * @li if it's set to 1 the returned delay is in seconds
+ * @li if it's set to 1000 the returned delay is in milliseconds
+ * @li if it's set to the input sample rate then the returned
+ * delay is in input samples
+ * @li if it's set to the output sample rate then the returned
+ * delay is in output samples
+ * @li if it's the least common multiple of in_sample_rate and
+ * out_sample_rate then an exact rounding-free delay will be
+ * returned
+ * @returns the delay in 1 / @c base units.
*/
int64_t swr_get_delay(struct SwrContext *s, int64_t base);
--
1.9.1
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