making act segmenter

1 files changed, 509 insertions, 0 deletions

diff --git a/ffmpeg/libavformat/seek.c b/ffmpeg/libavformat/seek.c
new file mode 100644
index 0000000..0ae99eb
--- /dev/null
+++ b/ffmpeg/libavformat/seek.c
@@ -0,0 +1,509 @@
+/*
+ * seek utility functions for use within format handlers
+ *
+ * Copyright (c) 2009 Ivan Schreter
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "seek.h"
+#include "libavutil/mathematics.h"
+#include "libavutil/mem.h"
+#include "internal.h"
+
+// NOTE: implementation should be moved here in another patch, to keep patches
+// separated.
+
+/**
+ * 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_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     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 the current iteration
+} AVSyncPoint;
+
+/**
+ * Compute a distance between timestamps.
+ *
+ * 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
+ */
+static int64_t ts_distance(int64_t ts_hi,
+                           AVRational tb_hi,
+                           int64_t ts_lo,
+                           AVRational tb_lo)
+{
+    int64_t hi, lo;
+
+    hi = ts_hi * tb_hi.num * tb_lo.den;
+    lo = ts_lo * tb_lo.num * tb_hi.den;
+
+    return hi - lo;
+}
+
+/**
+ * Partial search for keyframes in multiple streams.
+ *
+ * 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 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          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,
+                                   AVRational timebase,
+                                   int flags,
+                                   AVSyncPoint *sync,
+                                   int keyframes_to_find,
+                                   int *found_lo,
+                                   int *found_hi,
+                                   int first_iter)
+{
+    AVPacket pkt;
+    AVSyncPoint *sp;
+    AVStream *st;
+    int idx;
+    int flg;
+    int terminated_count = 0;
+    int64_t pos;
+    int64_t pts, dts;   // PTS/DTS from stream
+    int64_t ts;         // PTS in stream-local time base or position for byte seeking
+    AVRational ts_tb;   // Time base of the stream or 1:1 for byte seeking
+
+    for (;;) {
+        if (av_read_frame(s, &pkt) < 0) {
+            // EOF or error, make sure high flags are set
+            for (idx = 0; idx < s->nb_streams; ++idx) {
+                if (s->streams[idx]->discard < AVDISCARD_ALL) {
+                    sp = &sync[idx];
+                    if (sp->pos_hi == INT64_MAX) {
+                        // no high frame exists for this stream
+                        (*found_hi)++;
+                        sp->ts_hi  = INT64_MAX;
+                        sp->pos_hi = INT64_MAX - 1;
+                    }
+                }
+            }
+            break;
+        }
+
+        idx = pkt.stream_index;
+        st = s->streams[idx];
+        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
+            pts = dts;
+
+        av_free_packet(&pkt);
+
+        // Multi-frame packets only return position for the very first frame.
+        // Other frames are read with position == -1. Therefore, we note down
+        // last known position of a frame and use it if a frame without
+        // 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)
+            pos = sp->last_pos;
+        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 & AV_PKT_FLAG_KEY) || (flags & AVSEEK_FLAG_ANY))) {
+            if (flags & AVSEEK_FLAG_BYTE) {
+                // for byte seeking, use position as timestamp
+                ts        = pos;
+                ts_tb.num = 1;
+                ts_tb.den = 1;
+            } else {
+                // otherwise, get stream time_base
+                ts    = pts;
+                ts_tb = st->time_base;
+            }
+
+            if (sp->first_ts == AV_NOPTS_VALUE) {
+                // Note down termination timestamp for the next iteration - when
+                // we encounter a packet with the same timestamp, we will ignore
+                // any further packets for this stream in next iteration (as they
+                // are already evaluated).
+                sp->first_ts    = ts;
+                sp->first_ts_tb = ts_tb;
+            }
+
+            if (sp->term_ts != AV_NOPTS_VALUE &&
+                av_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
+                        (*found_hi)++;
+                        sp->ts_hi  = INT64_MAX;
+                        sp->pos_hi = INT64_MAX - 1;
+                    }
+                    if (terminated_count == keyframes_to_find)
+                        break;  // all terminated, iteration done
+                }
+                continue;
+            }
+
+            if (av_compare_ts(ts, ts_tb, timestamp, timebase) <= 0) {
+                // keyframe found before target timestamp
+                if (sp->pos_lo == INT64_MAX) {
+                    // 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)
+                    sp->ts_lo  = ts;
+                    sp->pos_lo = pos;
+                }
+            }
+            if (av_compare_ts(ts, ts_tb, timestamp, timebase) >= 0) {
+                // keyframe found after target timestamp
+                if (sp->pos_hi == INT64_MAX) {
+                    // found first keyframe higher than target timestamp
+                    (*found_hi)++;
+                    sp->ts_hi  = ts;
+                    sp->pos_hi = pos;
+                    if (*found_hi >= keyframes_to_find && first_iter) {
+                        // We found high frame for all. They may get updated
+                        // to TS closer to target TS in later iterations (which
+                        // will stop at start position of previous iteration).
+                        break;
+                    }
+                } else if (sp->ts_hi > ts) {
+                    // found a better match (actually, shouldn't happen)
+                    sp->ts_hi  = ts;
+                    sp->pos_hi = pos;
+                }
+            }
+        }
+    }
+
+    // Clean up the parser.
+    ff_read_frame_flush(s);
+}
+
+int64_t ff_gen_syncpoint_search(AVFormatContext *s,
+                                int stream_index,
+                                int64_t pos,
+                                int64_t ts_min,
+                                int64_t ts,
+                                int64_t ts_max,
+                                int flags)
+{
+    AVSyncPoint *sync, *sp;
+    AVStream *st;
+    int i;
+    int keyframes_to_find = 0;
+    int64_t curpos;
+    int64_t step;
+    int found_lo = 0, found_hi = 0;
+    int64_t min_distance, distance;
+    int64_t min_pos = 0;
+    int first_iter = 1;
+    AVRational time_base;
+
+    if (flags & AVSEEK_FLAG_BYTE) {
+        // 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
+            st = s->streams[stream_index];
+            time_base = st->time_base;
+        } else {
+            // 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 = 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];
+
+        sp->pos_lo     = INT64_MAX;
+        sp->ts_lo      = INT64_MAX;
+        sp->pos_hi     = INT64_MAX;
+        sp->ts_hi      = INT64_MAX;
+        sp->terminated = 0;
+        sp->first_ts   = AV_NOPTS_VALUE;
+        sp->term_ts    = ts_max;
+        sp->term_ts_tb = time_base;
+        sp->last_pos   = pos;
+
+        st->cur_dts    = AV_NOPTS_VALUE;
+
+        if (st->discard < AVDISCARD_ALL)
+            ++keyframes_to_find;
+    }
+
+    if (!keyframes_to_find) {
+        // no stream active, error
+        av_free(sync);
+        return -1;
+    }
+
+    // Find keyframes in all active streams with timestamp/position just before
+    // and just after requested timestamp/position.
+    step = s->pb->buffer_size;
+    curpos = FFMAX(pos - step / 2, 0);
+    for (;;) {
+        avio_seek(s->pb, curpos, SEEK_SET);
+        search_hi_lo_keyframes(s,
+                               ts, time_base,
+                               flags,
+                               sync,
+                               keyframes_to_find,
+                               &found_lo, &found_hi,
+                               first_iter);
+        if (found_lo == keyframes_to_find && found_hi == keyframes_to_find)
+            break;  // have all keyframes we wanted
+        if (!curpos)
+            break;  // cannot go back anymore
+
+        curpos = pos - step;
+        if (curpos < 0)
+            curpos = 0;
+        step *= 2;
+
+        // switch termination positions
+        for (i = 0; i < s->nb_streams; ++i) {
+            st = s->streams[i];
+            st->cur_dts = AV_NOPTS_VALUE;
+
+            sp = &sync[i];
+            if (sp->first_ts != AV_NOPTS_VALUE) {
+                sp->term_ts    = sp->first_ts;
+                sp->term_ts_tb = sp->first_ts_tb;
+                sp->first_ts   = AV_NOPTS_VALUE;
+            }
+            sp->terminated = 0;
+            sp->last_pos = curpos;
+        }
+        first_iter = 0;
+    }
+
+    // Find actual position to start decoding so that decoder synchronizes
+    // closest to ts and between ts_min and ts_max.
+    pos = INT64_MAX;
+
+    for (i = 0; i < s->nb_streams; ++i) {
+        st = s->streams[i];
+        if (st->discard < AVDISCARD_ALL) {
+            sp = &sync[i];
+            min_distance = INT64_MAX;
+            // Find timestamp closest to requested timestamp within min/max limits.
+            if (sp->pos_lo != INT64_MAX
+                && av_compare_ts(ts_min, time_base, sp->ts_lo, st->time_base) <= 0
+                && av_compare_ts(sp->ts_lo, st->time_base, ts_max, time_base) <= 0) {
+                // low timestamp is in range
+                min_distance = ts_distance(ts, time_base, sp->ts_lo, st->time_base);
+                min_pos = sp->pos_lo;
+            }
+            if (sp->pos_hi != INT64_MAX
+                && av_compare_ts(ts_min, time_base, sp->ts_hi, st->time_base) <= 0
+                && av_compare_ts(sp->ts_hi, st->time_base, ts_max, time_base) <= 0) {
+                // high timestamp is in range, check distance
+                distance = ts_distance(sp->ts_hi, st->time_base, ts, time_base);
+                if (distance < min_distance) {
+                    min_distance = distance;
+                    min_pos = sp->pos_hi;
+                }
+            }
+            if (min_distance == INT64_MAX) {
+                // no timestamp is in range, cannot seek
+                av_free(sync);
+                return -1;
+            }
+            if (min_pos < pos)
+                pos = min_pos;
+        }
+    }
+
+    avio_seek(s->pb, pos, SEEK_SET);
+    av_free(sync);
+    return pos;
+}
+
+AVParserState *ff_store_parser_state(AVFormatContext *s)
+{
+    int i;
+    AVStream *st;
+    AVParserStreamState *ss;
+    AVParserState *state = av_malloc(sizeof(AVParserState));
+    if (!state)
+        return NULL;
+
+    state->stream_states = av_malloc(sizeof(AVParserStreamState) * s->nb_streams);
+    if (!state->stream_states) {
+        av_free(state);
+        return NULL;
+    }
+
+    state->fpos = avio_tell(s->pb);
+
+    // copy context structures
+    state->packet_buffer                    = s->packet_buffer;
+    state->parse_queue                      = s->parse_queue;
+    state->raw_packet_buffer                = s->raw_packet_buffer;
+    state->raw_packet_buffer_remaining_size = s->raw_packet_buffer_remaining_size;
+
+    s->packet_buffer                        = NULL;
+    s->parse_queue                          = NULL;
+    s->raw_packet_buffer                    = NULL;
+    s->raw_packet_buffer_remaining_size     = RAW_PACKET_BUFFER_SIZE;
+
+    // copy stream structures
+    state->nb_streams = s->nb_streams;
+    for (i = 0; i < s->nb_streams; i++) {
+        st = s->streams[i];
+        ss = &state->stream_states[i];
+
+        ss->parser        = st->parser;
+        ss->last_IP_pts   = st->last_IP_pts;
+        ss->cur_dts       = st->cur_dts;
+        ss->reference_dts = st->reference_dts;
+        ss->probe_packets = st->probe_packets;
+
+        st->parser        = NULL;
+        st->last_IP_pts   = AV_NOPTS_VALUE;
+        st->cur_dts       = AV_NOPTS_VALUE;
+        st->reference_dts = AV_NOPTS_VALUE;
+        st->probe_packets = MAX_PROBE_PACKETS;
+    }
+
+    return state;
+}
+
+void ff_restore_parser_state(AVFormatContext *s, AVParserState *state)
+{
+    int i;
+    AVStream *st;
+    AVParserStreamState *ss;
+    ff_read_frame_flush(s);
+
+    if (!state)
+        return;
+
+    avio_seek(s->pb, state->fpos, SEEK_SET);
+
+    // copy context structures
+    s->packet_buffer                    = state->packet_buffer;
+    s->parse_queue                      = state->parse_queue;
+    s->raw_packet_buffer                = state->raw_packet_buffer;
+    s->raw_packet_buffer_remaining_size = state->raw_packet_buffer_remaining_size;
+
+    // copy stream structures
+    for (i = 0; i < state->nb_streams; i++) {
+        st = s->streams[i];
+        ss = &state->stream_states[i];
+
+        st->parser        = ss->parser;
+        st->last_IP_pts   = ss->last_IP_pts;
+        st->cur_dts       = ss->cur_dts;
+        st->reference_dts = ss->reference_dts;
+        st->probe_packets = ss->probe_packets;
+    }
+
+    av_free(state->stream_states);
+    av_free(state);
+}
+
+static void free_packet_list(AVPacketList *pktl)
+{
+    AVPacketList *cur;
+    while (pktl) {
+        cur = pktl;
+        pktl = cur->next;
+        av_free_packet(&cur->pkt);
+        av_free(cur);
+    }
+}
+
+void ff_free_parser_state(AVFormatContext *s, AVParserState *state)
+{
+    int i;
+    AVParserStreamState *ss;
+
+    if (!state)
+        return;
+
+    for (i = 0; i < state->nb_streams; i++) {
+        ss = &state->stream_states[i];
+        if (ss->parser)
+            av_parser_close(ss->parser);
+    }
+
+    free_packet_list(state->packet_buffer);
+    free_packet_list(state->parse_queue);
+    free_packet_list(state->raw_packet_buffer);
+
+    av_free(state->stream_states);
+    av_free(state);
+}