[FFmpeg-cvslog] r19773 - in trunk/libavformat: seek.c seek.h
schreter
subversion
Sat Sep 5 21:31:01 CEST 2009
Author: schreter
Date: Sat Sep 5 21:31:01 2009
New Revision: 19773
Log:
cosmetic changes (indentation, doxygen comments, braces, put structures for API to header, ...)
Modified:
trunk/libavformat/seek.c
trunk/libavformat/seek.h
Modified: trunk/libavformat/seek.c
==============================================================================
--- trunk/libavformat/seek.c Sat Sep 5 21:14:44 2009 (r19772)
+++ trunk/libavformat/seek.c Sat Sep 5 21:31:01 2009 (r19773)
@@ -1,5 +1,5 @@
/*
- * Utility functions for seeking for use within FFmpeg format handlers.
+ * seek utility functions for use within format handlers
*
* Copyright (c) 2009 Ivan Schreter
*
@@ -28,65 +28,33 @@
extern void av_read_frame_flush(AVFormatContext *s);
/**
- * Helper structure to store parser state of AVStream.
- */
-typedef struct AVStreamState {
- // Saved members of AVStream
- AVCodecParserContext *parser;
- AVPacket cur_pkt;
- int64_t last_IP_pts;
- int64_t cur_dts;
- int64_t reference_dts;
- const uint8_t *cur_ptr;
- int cur_len;
- int probe_packets;
-} AVStreamState;
-
-/**
- * Helper structure to store parser state of AVFormat.
- */
-struct AVParserState {
- int64_t fpos; ///< File position at the time of call.
-
- // Saved members of AVFormatContext
- AVStream *cur_st; ///< Current stream.
- AVPacketList *packet_buffer; ///< Packet buffer of original state.
- AVPacketList *raw_packet_buffer; ///< Raw packet buffer of original state.
- int raw_packet_buffer_remaining_size; ///< Remaining size available for raw_packet_buffer.
-
- // Saved info for streams.
- int nb_streams; ///< Number of streams with stored state.
- AVStreamState *stream_states; ///< States of individual streams (array).
-};
-
-/**
- * Helper structure describing keyframe search state of one stream.
+ * helper structure describing keyframe search state of one stream
*/
typedef struct {
- int64_t pos_lo; ///< Position of the frame with low timestamp in file or INT64_MAX if not found (yet).
- int64_t ts_lo; ///< Frame presentation timestamp or same as pos_lo for byte seeking.
+ int64_t pos_lo; ///< position of the frame with low timestamp in file or INT64_MAX if not found (yet)
+ int64_t ts_lo; ///< frame presentation timestamp or same as pos_lo for byte seeking
- int64_t pos_hi; ///< Position of the frame with high timestamp in file or INT64_MAX if not found (yet).
- int64_t ts_hi; ///< Frame presentation timestamp or same as pos_hi for byte seeking.
+ int64_t pos_hi; ///< position of the frame with high timestamp in file or INT64_MAX if not found (yet)
+ int64_t ts_hi; ///< frame presentation timestamp or same as pos_hi for byte seeking
- int64_t last_pos; ///< Last known position of a frame, for multi-frame packets.
+ int64_t last_pos; ///< last known position of a frame, for multi-frame packets
- int64_t term_ts; ///< Termination timestamp (which TS we already read).
- AVRational term_ts_tb; ///< Timebase for term_ts.
- int64_t first_ts; ///< First packet timestamp in this iteration (to fill term_ts later).
- AVRational first_ts_tb;///< Timebase for first_ts.
+ int64_t term_ts; ///< termination timestamp (which TS we already read)
+ AVRational term_ts_tb; ///< timebase for term_ts
+ int64_t first_ts; ///< first packet timestamp in this iteration (to fill term_ts later)
+ AVRational first_ts_tb; ///< timebase for first_ts
- int terminated; ///< Termination flag for current iteration.
+ int terminated; ///< termination flag for the current iteration
} AVSyncPoint;
/**
- * Compare two timestamps exactly, taking into account their respective time bases.
+ * Compare two timestamps exactly, taking their respective time bases into account.
*
- * @param ts_a timestamp A.
- * @param tb_a time base for timestamp A.
- * @param ts_b timestamp B.
- * @param tb_b time base for timestamp A.
- * @return -1. 0 or 1 if timestamp A is less than, equal or greater than timestamp B.
+ * @param ts_a timestamp A
+ * @param tb_a time base for timestamp A
+ * @param ts_b timestamp B
+ * @param tb_b time base for timestamp A
+ * @return -1, 0 or 1 if timestamp A is less than, equal or greater than timestamp B
*/
static int compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b)
{
@@ -95,9 +63,9 @@ static int compare_ts(int64_t ts_a, AVRa
if (ts_a == INT64_MIN)
return ts_a < ts_b ? -1 : 0;
if (ts_a == INT64_MAX)
- return ts_a > ts_b ? 1 : 0;
+ return ts_a > ts_b ? 1 : 0;
if (ts_b == INT64_MIN)
- return ts_a > ts_b ? 1 : 0;
+ return ts_a > ts_b ? 1 : 0;
if (ts_b == INT64_MAX)
return ts_a < ts_b ? -1 : 0;
@@ -105,7 +73,7 @@ static int compare_ts(int64_t ts_a, AVRa
b = ts_b * tb_b.num * tb_a.den;
res = a - b;
- if (res == 0)
+ if (!res)
return 0;
else
return (res >> 63) | 1;
@@ -117,13 +85,16 @@ static int compare_ts(int64_t ts_a, AVRa
* Distances are only comparable, if same time bases are used for computing
* distances.
*
- * @param ts_hi high timestamp.
- * @param tb_hi high timestamp time base.
- * @param ts_lo low timestamp.
- * @param tb_lo low timestamp time base.
- * @return representation of distance between high and low timestamps.
+ * @param ts_hi high timestamp
+ * @param tb_hi high timestamp time base
+ * @param ts_lo low timestamp
+ * @param tb_lo low timestamp time base
+ * @return representation of distance between high and low timestamps
*/
-static int64_t ts_distance(int64_t ts_hi, AVRational tb_hi, int64_t ts_lo, AVRational tb_lo)
+static int64_t ts_distance(int64_t ts_hi,
+ AVRational tb_hi,
+ int64_t ts_lo,
+ AVRational tb_lo)
{
int64_t hi, lo;
@@ -136,23 +107,23 @@ static int64_t ts_distance(int64_t ts_hi
/**
* Partial search for keyframes in multiple streams.
*
- * This routine searches for the next lower and next higher timestamp to
- * given target timestamp in each stream, starting at current file position
- * and ending at position, where all streams have already been examined
- * (or when all higher key frames found in first iteration).
+ * This routine searches in each stream for the next lower and the next higher
+ * timestamp compared to the given target timestamp. The search starts at the current
+ * file position and ends at the file position, where all streams have already been
+ * examined (or when all higher key frames are found in the first iteration).
*
- * This routine is called iteratively with exponential backoff to find lower
+ * This routine is called iteratively with an exponential backoff to find the lower
* timestamp.
*
- * @param s format context.
- * @param timestamp target timestamp (or position, if AVSEEK_FLAG_BYTE).
- * @param timebase time base for timestamps.
- * @param flags seeking flags.
- * @param sync array with information per stream.
- * @param keyframes_to_find count of keyframes to find in total.
- * @param found_lo pointer to count of already found low timestamp keyframes.
- * @param found_hi pointer to count of already found high timestamp keyframes.
- * @param first_iter flag for first iteration.
+ * @param s format context
+ * @param timestamp target timestamp (or position, if AVSEEK_FLAG_BYTE)
+ * @param timebase time base for timestamps
+ * @param flags seeking flags
+ * @param sync array with information per stream
+ * @param keyframes_to_find count of keyframes to find in total
+ * @param found_lo ptr to the count of already found low timestamp keyframes
+ * @param found_hi ptr to the count of already found high timestamp keyframes
+ * @param first_iter flag for first iteration
*/
static void search_hi_lo_keyframes(AVFormatContext *s,
int64_t timestamp,
@@ -182,7 +153,7 @@ static void search_hi_lo_keyframes(AVFor
if (s->streams[idx]->discard < AVDISCARD_ALL) {
sp = &sync[idx];
if (sp->pos_hi == INT64_MAX) {
- // No high frame exists for this stream
+ // no high frame exists for this stream
(*found_hi)++;
sp->ts_hi = INT64_MAX;
sp->pos_hi = INT64_MAX - 1;
@@ -194,20 +165,20 @@ static void search_hi_lo_keyframes(AVFor
idx = pkt.stream_index;
st = s->streams[idx];
- if (st->discard >= AVDISCARD_ALL) {
- // This stream is not active, skip packet.
+ if (st->discard >= AVDISCARD_ALL)
+ // this stream is not active, skip packet
continue;
- }
+
sp = &sync[idx];
flg = pkt.flags;
pos = pkt.pos;
pts = pkt.pts;
dts = pkt.dts;
- if (pts == AV_NOPTS_VALUE) {
- // Some formats don't provide PTS, only DTS.
+ if (pts == AV_NOPTS_VALUE)
+ // some formats don't provide PTS, only DTS
pts = dts;
- }
+
av_free_packet(&pkt);
// Multi-frame packets only return position for the very first frame.
@@ -216,21 +187,21 @@ static void search_hi_lo_keyframes(AVFor
// position arrives. In this way, it's possible to seek to proper
// position. Additionally, for parsers not providing position at all,
// an approximation will be used (starting position of this iteration).
- if (pos < 0) {
+ if (pos < 0)
pos = sp->last_pos;
- } else {
+ else
sp->last_pos = pos;
- }
// Evaluate key frames with known TS (or any frames, if AVSEEK_FLAG_ANY set).
- if (pts != AV_NOPTS_VALUE && ((flg & PKT_FLAG_KEY) || (flags & AVSEEK_FLAG_ANY))) {
+ if (pts != AV_NOPTS_VALUE &&
+ ((flg & PKT_FLAG_KEY) || (flags & AVSEEK_FLAG_ANY))) {
if (flags & AVSEEK_FLAG_BYTE) {
- // For byte seeking, use position as timestamp.
+ // for byte seeking, use position as timestamp
ts = pos;
ts_tb.num = 1;
ts_tb.den = 1;
} else {
- // Get stream time_base.
+ // otherwise, get stream time_base
ts = pts;
ts_tb = st->time_base;
}
@@ -244,13 +215,14 @@ static void search_hi_lo_keyframes(AVFor
sp->first_ts_tb = ts_tb;
}
- if (sp->term_ts != AV_NOPTS_VALUE && compare_ts(ts, ts_tb, sp->term_ts, sp->term_ts_tb) > 0) {
- // We are past the end position from last iteration, ignore packet.
+ if (sp->term_ts != AV_NOPTS_VALUE &&
+ compare_ts(ts, ts_tb, sp->term_ts, sp->term_ts_tb) > 0) {
+ // past the end position from last iteration, ignore packet
if (!sp->terminated) {
sp->terminated = 1;
++terminated_count;
if (sp->pos_hi == INT64_MAX) {
- // No high frame exists for this stream
+ // no high frame exists for this stream
(*found_hi)++;
sp->ts_hi = INT64_MAX;
sp->pos_hi = INT64_MAX - 1;
@@ -262,22 +234,22 @@ static void search_hi_lo_keyframes(AVFor
}
if (compare_ts(ts, ts_tb, timestamp, timebase) <= 0) {
- // Keyframe found before target timestamp.
+ // keyframe found before target timestamp
if (sp->pos_lo == INT64_MAX) {
- // Found first keyframe lower than target timestamp.
+ // found first keyframe lower than target timestamp
(*found_lo)++;
sp->ts_lo = ts;
sp->pos_lo = pos;
} else if (sp->ts_lo < ts) {
- // Found a better match (closer to target timestamp).
+ // found a better match (closer to target timestamp)
sp->ts_lo = ts;
sp->pos_lo = pos;
}
}
if (compare_ts(ts, ts_tb, timestamp, timebase) >= 0) {
- // Keyframe found after target timestamp.
+ // keyframe found after target timestamp
if (sp->pos_hi == INT64_MAX) {
- // Found first keyframe higher than target timestamp.
+ // found first keyframe higher than target timestamp
(*found_hi)++;
sp->ts_hi = ts;
sp->pos_hi = pos;
@@ -288,7 +260,7 @@ static void search_hi_lo_keyframes(AVFor
break;
}
} else if (sp->ts_hi > ts) {
- // Found a better match (actually, shouldn't happen).
+ // found a better match (actually, shouldn't happen)
sp->ts_hi = ts;
sp->pos_hi = pos;
}
@@ -321,27 +293,27 @@ int64_t ff_gen_syncpoint_search(AVFormat
AVRational time_base;
if (flags & AVSEEK_FLAG_BYTE) {
- /* For byte seeking, we have exact 1:1 "timestamps" - positions */
+ // for byte seeking, we have exact 1:1 "timestamps" - positions
time_base.num = 1;
time_base.den = 1;
} else {
if (stream_index >= 0) {
- /* We have a reference stream, which time base we use */
+ // we have a reference stream, which time base we use
st = s->streams[stream_index];
time_base = st->time_base;
} else {
- /* No reference stream, use AV_TIME_BASE as reference time base */
+ // no reference stream, use AV_TIME_BASE as reference time base
time_base.num = 1;
time_base.den = AV_TIME_BASE;
}
}
// Initialize syncpoint structures for each stream.
- sync = (AVSyncPoint*) av_malloc(s->nb_streams * sizeof(AVSyncPoint));
- if (!sync) {
+ sync = av_malloc(s->nb_streams * sizeof(AVSyncPoint));
+ if (!sync)
// cannot allocate helper structure
return -1;
- }
+
for (i = 0; i < s->nb_streams; ++i) {
st = s->streams[i];
sp = &sync[i];
@@ -362,8 +334,8 @@ int64_t ff_gen_syncpoint_search(AVFormat
++keyframes_to_find;
}
- if (keyframes_to_find == 0) {
- // No stream active, error.
+ if (!keyframes_to_find) {
+ // no stream active, error
av_free(sync);
return -1;
}
@@ -383,7 +355,7 @@ int64_t ff_gen_syncpoint_search(AVFormat
first_iter);
if (found_lo == keyframes_to_find && found_hi == keyframes_to_find)
break; // have all keyframes we wanted
- if (curpos == 0)
+ if (!curpos)
break; // cannot go back anymore
curpos = pos - step;
@@ -454,12 +426,12 @@ AVParserState *ff_store_parser_state(AVF
{
int i;
AVStream *st;
- AVStreamState *ss;
- AVParserState *state = (AVParserState*) av_malloc(sizeof(AVParserState));
+ AVParserStreamState *ss;
+ AVParserState *state = av_malloc(sizeof(AVParserState));
if (!state)
return NULL;
- state->stream_states = (AVStreamState*) av_malloc(sizeof(AVStreamState) * s->nb_streams);
+ state->stream_states = av_malloc(sizeof(AVParserStreamState) * s->nb_streams);
if (!state->stream_states) {
av_free(state);
return NULL;
@@ -510,7 +482,7 @@ void ff_restore_parser_state(AVFormatCon
{
int i;
AVStream *st;
- AVStreamState *ss;
+ AVParserStreamState *ss;
av_read_frame_flush(s);
if (!state)
@@ -557,7 +529,7 @@ static void free_packet_list(AVPacketLis
void ff_free_parser_state(AVFormatContext *s, AVParserState *state)
{
int i;
- AVStreamState *ss;
+ AVParserStreamState *ss;
if (!state)
return;
Modified: trunk/libavformat/seek.h
==============================================================================
--- trunk/libavformat/seek.h Sat Sep 5 21:14:44 2009 (r19772)
+++ trunk/libavformat/seek.h Sat Sep 5 21:31:01 2009 (r19773)
@@ -1,5 +1,5 @@
/*
- * Utility functions for seeking for use within FFmpeg format handlers.
+ * seek utility functions for use within format handlers
*
* Copyright (c) 2009 Ivan Schreter
*
@@ -25,30 +25,59 @@
#include "avformat.h"
-/// Opaque structure for parser state.
-typedef struct AVParserState AVParserState;
+/**
+ * structure to store parser state of one AVStream
+ */
+typedef struct AVParserStreamState {
+ // saved members of AVStream
+ AVCodecParserContext *parser;
+ AVPacket cur_pkt;
+ int64_t last_IP_pts;
+ int64_t cur_dts;
+ int64_t reference_dts;
+ const uint8_t *cur_ptr;
+ int cur_len;
+ int probe_packets;
+} AVParserStreamState;
/**
- * Search for sync point of all active streams.
+ * structure to store parser state of AVFormat
+ */
+typedef struct AVParserState {
+ int64_t fpos; ///< file position at the time of call
+
+ // saved members of AVFormatContext
+ AVStream *cur_st; ///< current stream.
+ AVPacketList *packet_buffer; ///< packet buffer of original state
+ AVPacketList *raw_packet_buffer; ///< raw packet buffer of original state
+ int raw_packet_buffer_remaining_size; ///< remaining space in raw_packet_buffer
+
+ // saved info for streams
+ int nb_streams; ///< number of streams with stored state
+ AVParserStreamState *stream_states; ///< states of individual streams (array)
+} AVParserState;
+
+/**
+ * Search for the sync point of all active streams.
*
- * This is not supposed to be called directly by a user application,
+ * This routine is not supposed to be called directly by a user application,
* but by demuxers.
*
- * A sync point is a point in stream, so that decoding from this point,
- * output of decoders of all streams synchronizes closest to given timestamp
- * ts (but taking timestamp limits into account, i.e., no sooner than ts_min
- * and no later than ts_max).
+ * A sync point is defined as a point in stream, such that, when decoding start
+ * from this point, the decoded output of all streams synchronizes closest
+ * to the given timestamp ts. This routine also takes timestamp limits into account.
+ * Thus, the output will synchronize no sooner than ts_min and no later than ts_max.
*
- * @param stream_index stream index for time base reference of timestamps.
- * @param pos approximate position where to start searching for key frames.
- * @param min_ts minimum allowed timestamp (position, if AVSEEK_FLAG_BYTE set).
- * @param ts target timestamp (or position, if AVSEEK_FLAG_BYTE set in flags).
- * @param max_ts maximum allowed timestamp (position, if AVSEEK_FLAG_BYTE set).
- * @param flags if AVSEEK_FLAG_ANY is set, seek to any frame, otherwise only
- * to a keyframe. If AVSEEK_FLAG_BYTE is set, search by
- * position, not by timestamp.
- * @return < 0 if no such sync point could be found, otherwise stream position
- * (stream is repositioned to this position).
+ * @param stream_index stream index for time base reference of timestamps
+ * @param pos approximate position where to start searching for key frames
+ * @param min_ts minimum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
+ * @param ts target timestamp (or position, if AVSEEK_FLAG_BYTE set in flags)
+ * @param max_ts maximum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
+ * @param flags if AVSEEK_FLAG_ANY is set, seek to any frame, otherwise only
+ * to a keyframe. If AVSEEK_FLAG_BYTE is set, search by
+ * position, not by timestamp.
+ * @return -1 if no such sync point could be found, otherwise stream position
+ * (stream is repositioned to this position)
*/
int64_t ff_gen_syncpoint_search(AVFormatContext *s,
int stream_index,
@@ -61,16 +90,16 @@ int64_t ff_gen_syncpoint_search(AVFormat
/**
* Store current parser state and file position.
*
- * This function can be used by demuxers before destructive seeking algorithm
- * to store parser state. After the seek, depending on outcome, original state
- * can be restored or new state kept and original state freed.
+ * This function can be used by demuxers before a destructive seeking algorithm
+ * to store the parser state. Depending on the outcome of the seek, either the original
+ * state can be restored or the new state kept and the original state freed.
*
- * @note As a side effect, original parser state is reset, since structures
- * are relinked to stored state instead of being deeply-copied (for
- * performance reasons and to keep code simple).
+ * @note As a side effect, the original parser state is reset, since structures
+ * are relinked to the stored state instead of being deeply-copied (for
+ * performance reasons and to keep the code simple).
*
- * @param s context from which to save state.
- * @return parser state object or NULL if memory could not be allocated.
+ * @param s context from which to save state
+ * @return parser state object or NULL if memory could not be allocated
*/
AVParserState *ff_store_parser_state(AVFormatContext *s);
@@ -78,19 +107,19 @@ AVParserState *ff_store_parser_state(AVF
* Restore previously saved parser state and file position.
*
* Saved state will be invalidated and freed by this call, since internal
- * structures will be relinked back to stored state instead of being
+ * structures will be relinked back to the stored state instead of being
* deeply-copied.
*
- * @param s context to which to restore state (same as used for storing state).
- * @param state state to restore.
+ * @param s context to which to restore state (same as used for storing state)
+ * @param state state to restore
*/
void ff_restore_parser_state(AVFormatContext *s, AVParserState *state);
/**
* Free previously saved parser state.
*
- * @param s context to which the state belongs (same as used for storing state).
- * @param state state to free.
+ * @param s context to which the state belongs (same as used for storing state)
+ * @param state state to free
*/
void ff_free_parser_state(AVFormatContext *s, AVParserState *state);
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