Skip to content

F
ffmpeg.wasm-core
Commit 7a656933 authored by Ivan Schreter's avatar Ivan Schreter
Browse files
Options

cosmetic changes (indentation, doxygen comments, braces, put structures for API to header, ...) 

Originally committed as revision 19773 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 64b8e620
Show whitespace changes
Inline Side-by-side
Showing with 142 additions and 141 deletions
libavformat/seek.c
View file @ 7a656933
/*
* 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)
{
......@@ -105,7 +73,7 @@ static int compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb
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, AVRational tb_a, int64_t ts_b, AVRational tb
* 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, AVRational tb_hi, int64_t ts_lo, AVRat
/**
* 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(AVFormatContext *s,
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(AVFormatContext *s,
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(AVFormatContext *s,
// 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(AVFormatContext *s,
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(AVFormatContext *s,
}
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(AVFormatContext *s,
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(AVFormatContext *s,
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(AVFormatContext *s,
++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(AVFormatContext *s,
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(AVFormatContext *s)
{
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(AVFormatContext *s, AVParserState *state)
{
int i;
AVStream *st;
AVStreamState *ss;
AVParserStreamState *ss;
av_read_frame_flush(s);
if (!state)
......@@ -557,7 +529,7 @@ static void free_packet_list(AVPacketList *pktl)
void ff_free_parser_state(AVFormatContext *s, AVParserState *state)
{
int i;
AVStreamState *ss;
AVParserStreamState *ss;
if (!state)
return;
......
libavformat/seek.h
View file @ 7a656933
/*
* 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;
/**
* 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 sync point of all active streams.
* 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 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).
* @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(AVFormatContext *s,
/**
* 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(AVFormatContext *s);
* 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);
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment