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avformat/async: cache some data for fast seek backward
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
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87ff61b9ab
commit
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@ -24,7 +24,6 @@
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/**
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* @TODO
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* support timeout
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* support backward short seek
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* support work with concatdec, hls
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*/
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@ -43,8 +42,17 @@
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#endif
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#define BUFFER_CAPACITY (4 * 1024 * 1024)
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#define READ_BACK_CAPACITY (4 * 1024 * 1024)
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#define SHORT_SEEK_THRESHOLD (256 * 1024)
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typedef struct RingBuffer
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{
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AVFifoBuffer *fifo;
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int read_back_capacity;
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int read_pos;
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} RingBuffer;
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typedef struct Context {
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AVClass *class;
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URLContext *inner;
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@ -61,7 +69,7 @@ typedef struct Context {
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int64_t logical_pos;
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int64_t logical_size;
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AVFifoBuffer *fifo;
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RingBuffer ring;
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pthread_cond_t cond_wakeup_main;
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pthread_cond_t cond_wakeup_background;
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@ -72,6 +80,73 @@ typedef struct Context {
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AVIOInterruptCB interrupt_callback;
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} Context;
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static int ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capacity)
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{
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memset(ring, 0, sizeof(RingBuffer));
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ring->fifo = av_fifo_alloc(capacity + read_back_capacity);
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if (!ring->fifo)
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return AVERROR(ENOMEM);
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ring->read_back_capacity = read_back_capacity;
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return 0;
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}
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static void ring_destroy(RingBuffer *ring)
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{
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av_fifo_freep(&ring->fifo);
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}
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static void ring_reset(RingBuffer *ring)
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{
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av_fifo_reset(ring->fifo);
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ring->read_pos = 0;
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}
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static int ring_size(RingBuffer *ring)
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{
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return av_fifo_size(ring->fifo) - ring->read_pos;
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}
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static int ring_space(RingBuffer *ring)
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{
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return av_fifo_space(ring->fifo);
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}
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static int ring_generic_read(RingBuffer *ring, void *dest, int buf_size, void (*func)(void*, void*, int))
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{
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int ret;
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av_assert2(buf_size <= ring_size(ring));
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ret = av_fifo_generic_peek_at(ring->fifo, dest, ring->read_pos, buf_size, func);
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ring->read_pos += buf_size;
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if (ring->read_pos > ring->read_back_capacity) {
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av_fifo_drain(ring->fifo, ring->read_pos - ring->read_back_capacity);
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ring->read_pos = ring->read_back_capacity;
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}
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return ret;
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}
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static int ring_generic_write(RingBuffer *ring, void *src, int size, int (*func)(void*, void*, int))
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{
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av_assert2(size <= ring_space(ring));
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return av_fifo_generic_write(ring->fifo, src, size, func);
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}
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static int ring_size_of_read_back(RingBuffer *ring)
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{
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return ring->read_pos;
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}
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static int ring_drain(RingBuffer *ring, int offset)
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{
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av_assert2(offset >= -ring_size_of_read_back(ring));
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av_assert2(offset <= -ring_size(ring));
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ring->read_pos += offset;
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return 0;
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}
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static int async_check_interrupt(void *arg)
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{
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URLContext *h = arg;
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@ -102,7 +177,7 @@ static void *async_buffer_task(void *arg)
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{
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URLContext *h = arg;
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Context *c = h->priv_data;
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AVFifoBuffer *fifo = c->fifo;
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RingBuffer *ring = &c->ring;
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int ret = 0;
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int64_t seek_ret;
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@ -132,14 +207,14 @@ static void *async_buffer_task(void *arg)
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c->seek_ret = seek_ret;
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c->seek_request = 0;
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av_fifo_reset(fifo);
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ring_reset(ring);
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pthread_cond_signal(&c->cond_wakeup_main);
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pthread_mutex_unlock(&c->mutex);
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continue;
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}
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fifo_space = av_fifo_space(fifo);
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fifo_space = ring_space(ring);
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if (c->io_eof_reached || fifo_space <= 0) {
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pthread_cond_signal(&c->cond_wakeup_main);
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pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
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@ -149,7 +224,7 @@ static void *async_buffer_task(void *arg)
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pthread_mutex_unlock(&c->mutex);
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to_copy = FFMIN(4096, fifo_space);
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ret = av_fifo_generic_write(fifo, (void *)h, to_copy, (void *)wrapped_url_read);
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ret = ring_generic_write(ring, (void *)h, to_copy, (void *)wrapped_url_read);
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pthread_mutex_lock(&c->mutex);
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if (ret <= 0) {
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@ -173,11 +248,9 @@ static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **
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av_strstart(arg, "async:", &arg);
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c->fifo = av_fifo_alloc(BUFFER_CAPACITY);
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if (!c->fifo) {
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ret = AVERROR(ENOMEM);
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ret = ring_init(&c->ring, BUFFER_CAPACITY, READ_BACK_CAPACITY);
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if (ret < 0)
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goto fifo_fail;
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}
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/* wrap interrupt callback */
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c->interrupt_callback = h->interrupt_callback;
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@ -225,7 +298,7 @@ cond_wakeup_main_fail:
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mutex_fail:
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ffurl_close(c->inner);
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url_fail:
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av_fifo_freep(&c->fifo);
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ring_destroy(&c->ring);
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fifo_fail:
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return ret;
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}
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@ -248,7 +321,7 @@ static int async_close(URLContext *h)
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pthread_cond_destroy(&c->cond_wakeup_main);
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pthread_mutex_destroy(&c->mutex);
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ffurl_close(c->inner);
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av_fifo_freep(&c->fifo);
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ring_destroy(&c->ring);
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return 0;
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}
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@ -257,7 +330,7 @@ static int async_read_internal(URLContext *h, void *dest, int size, int read_com
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void (*func)(void*, void*, int))
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{
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Context *c = h->priv_data;
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AVFifoBuffer *fifo = c->fifo;
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RingBuffer *ring = &c->ring;
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int to_read = size;
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int ret = 0;
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@ -269,10 +342,10 @@ static int async_read_internal(URLContext *h, void *dest, int size, int read_com
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ret = AVERROR_EXIT;
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break;
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}
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fifo_size = av_fifo_size(fifo);
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fifo_size = ring_size(ring);
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to_copy = FFMIN(to_read, fifo_size);
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if (to_copy > 0) {
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av_fifo_generic_read(fifo, dest, to_copy, func);
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ring_generic_read(ring, dest, to_copy, func);
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if (!func)
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dest = (uint8_t *)dest + to_copy;
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c->logical_pos += to_copy;
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@ -312,10 +385,11 @@ static void fifo_do_not_copy_func(void* dest, void* src, int size) {
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static int64_t async_seek(URLContext *h, int64_t pos, int whence)
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{
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Context *c = h->priv_data;
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AVFifoBuffer *fifo = c->fifo;
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RingBuffer *ring = &c->ring;
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int64_t ret;
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int64_t new_logical_pos;
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int fifo_size;
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int fifo_size_of_read_back;
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if (whence == AVSEEK_SIZE) {
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av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
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@ -332,17 +406,28 @@ static int64_t async_seek(URLContext *h, int64_t pos, int whence)
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if (new_logical_pos < 0)
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return AVERROR(EINVAL);
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fifo_size = av_fifo_size(fifo);
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fifo_size = ring_size(ring);
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fifo_size_of_read_back = ring_size_of_read_back(ring);
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if (new_logical_pos == c->logical_pos) {
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/* current position */
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return c->logical_pos;
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} else if ((new_logical_pos > c->logical_pos) &&
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} else if ((new_logical_pos >= (c->logical_pos - fifo_size_of_read_back)) &&
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(new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
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int pos_delta = (int)(new_logical_pos - c->logical_pos);
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/* fast seek */
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av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
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new_logical_pos, (int)c->logical_pos,
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(int)(new_logical_pos - c->logical_pos), fifo_size);
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async_read_internal(h, NULL, (int)(new_logical_pos - c->logical_pos), 1, fifo_do_not_copy_func);
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if (pos_delta > 0) {
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// fast seek forwards
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async_read_internal(h, NULL, pos_delta, 1, fifo_do_not_copy_func);
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} else {
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// fast seek backwards
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ring_drain(ring, pos_delta);
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c->logical_pos = new_logical_pos;
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}
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return c->logical_pos;
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} else if (c->logical_size <= 0) {
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/* can not seek */
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