[FFmpeg-devel] [PATCH] [RFC] avformat/async: support filling with a background thread.
Zhang Rui
bbcallen at gmail.com
Thu Jul 16 09:04:42 CEST 2015
---
configure | 1 +
libavformat/Makefile | 1 +
libavformat/allformats.c | 1 +
libavformat/async.c | 380 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 383 insertions(+)
create mode 100644 libavformat/async.c
diff --git a/configure b/configure
index 1cd9fd6..fa1868a 100755
--- a/configure
+++ b/configure
@@ -2638,6 +2638,7 @@ x11grab_indev_deps="x11grab"
x11grab_xcb_indev_deps="libxcb"
# protocols
+async_protocol_deps="pthreads"
bluray_protocol_deps="libbluray"
ffrtmpcrypt_protocol_deps="!librtmp_protocol"
ffrtmpcrypt_protocol_deps_any="gcrypt gmp openssl"
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 479361a..108b6a6 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -496,6 +496,7 @@ OBJS-$(CONFIG_LIBSSH_PROTOCOL) += libssh.o
OBJS-$(CONFIG_LIBSMBCLIENT_PROTOCOL) += libsmbclient.o
# protocols I/O
+OBJS-$(CONFIG_ASYNC_PROTOCOL) += async.o
OBJS-$(CONFIG_APPLEHTTP_PROTOCOL) += hlsproto.o
OBJS-$(CONFIG_BLURAY_PROTOCOL) += bluray.o
OBJS-$(CONFIG_CACHE_PROTOCOL) += cache.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 2caa6b1..181cb9e 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -351,6 +351,7 @@ void av_register_all(void)
/* protocols */
+ REGISTER_PROTOCOL(ASYNC, async);
REGISTER_PROTOCOL(BLURAY, bluray);
REGISTER_PROTOCOL(CACHE, cache);
REGISTER_PROTOCOL(CONCAT, concat);
diff --git a/libavformat/async.c b/libavformat/async.c
new file mode 100644
index 0000000..36c7a061
--- /dev/null
+++ b/libavformat/async.c
@@ -0,0 +1,380 @@
+/*
+ * Input async protocol.
+ * Copyright (c) 2015 Zhang Rui <bbcallen at gmail.com>
+ *
+ * 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
+ *
+ * Based on libavformat/cache.c by Michael Niedermayer
+ */
+
+ /**
+ * @TODO
+ * support timeout
+ * support backward short seek
+ * support work with concatdec, hls
+ */
+
+#include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
+#include "libavutil/error.h"
+#include "libavutil/fifo.h"
+#include "libavutil/log.h"
+#include "libavutil/opt.h"
+#include "url.h"
+#include <stdint.h>
+#include <pthread.h>
+#include <unistd.h>
+
+#define BUFFER_CAPACITY (4 * 1024 * 1024)
+#define SHORT_SEEK_THRESHOLD (256 * 1024)
+
+typedef struct Context {
+ AVClass *class;
+ URLContext *inner;
+
+ int seek_request;
+ size_t seek_pos;
+ int seek_whence;
+ int seek_completed;
+ int64_t seek_ret;
+
+ int io_error;
+ int io_eof_reached;
+
+ size_t logical_pos;
+ size_t logical_size;
+ AVFifoBuffer *fifo;
+
+ pthread_cond_t cond_wakeup_main;
+ pthread_cond_t cond_wakeup_background;
+ pthread_mutex_t mutex;
+ pthread_t async_buffer_thread;
+
+ int abort_request;
+ AVIOInterruptCB interrupt_callback;
+} Context;
+
+static int async_interrupt_callback(void *arg)
+{
+ URLContext *h = arg;
+ Context *c = h->priv_data;
+ int ret = 0;
+
+ if (c->interrupt_callback.callback) {
+ ret = c->interrupt_callback.callback(c->interrupt_callback.opaque);
+ if (!ret)
+ return ret;
+ }
+
+ return c->abort_request;
+}
+
+static void *async_buffer_task(void *arg)
+{
+ URLContext *h = arg;
+ Context *c = h->priv_data;
+ AVFifoBuffer *fifo = c->fifo;
+ int ret = 0;
+
+ while (1) {
+ if (async_interrupt_callback(h)) {
+ c->io_eof_reached = 1;
+ c->io_error = AVERROR_EXIT;
+ break;
+ }
+
+ if (c->seek_request) {
+ pthread_mutex_lock(&c->mutex);
+
+ ret = ffurl_seek(c->inner, c->seek_pos, c->seek_whence);
+ if (ret < 0) {
+ c->io_eof_reached = 1;
+ c->io_error = ret;
+ } else {
+ c->io_eof_reached = 0;
+ c->io_error = 0;
+ }
+
+ c->seek_completed = 1;
+ c->seek_ret = ret;
+ c->seek_request = 0;
+
+ av_fifo_reset(fifo);
+
+ pthread_cond_signal(&c->cond_wakeup_main);
+ pthread_mutex_unlock(&c->mutex);
+ continue;
+ }
+
+ int fifo_space = av_fifo_space(fifo);
+ if (c->io_eof_reached || fifo_space <= 0) {
+ pthread_mutex_lock(&c->mutex);
+ pthread_cond_signal(&c->cond_wakeup_main);
+ pthread_cond_wait(&c->cond_wakeup_background, &c->mutex);
+ pthread_mutex_unlock(&c->mutex);
+ continue;
+ }
+
+ int to_copy = FFMIN(4096, fifo_space);
+ ret = av_fifo_generic_write(fifo, c->inner, to_copy, (void *)ffurl_read);
+ if (ret <= 0) {
+ c->io_eof_reached = 1;
+ if (ret < 0) {
+ c->io_error = ret;
+ }
+ }
+
+ pthread_mutex_lock(&c->mutex);
+ pthread_cond_signal(&c->cond_wakeup_main);
+ pthread_mutex_unlock(&c->mutex);
+ }
+
+ return NULL;
+}
+
+static int async_open(URLContext *h, const char *arg, int flags, AVDictionary **options)
+{
+ Context *c = h->priv_data;
+ int ret;
+ AVIOInterruptCB interrupt_callback = {.callback = async_interrupt_callback, .opaque = h};
+
+ av_strstart(arg, "async:", &arg);
+
+ c->fifo = av_fifo_alloc(BUFFER_CAPACITY);
+ if (!c->fifo) {
+ ret = AVERROR(ENOMEM);
+ goto fifo_fail;
+ }
+
+ /* wrap interrupt callback */
+ c->interrupt_callback = h->interrupt_callback;
+ ret = ffurl_open(&c->inner, arg, flags, &interrupt_callback, options);
+ if (ret != 0) {
+ av_log(h, AV_LOG_ERROR, "ffurl_open failed : %s, %s\n", strerror(ret), arg);
+ goto url_fail;
+ }
+
+ c->logical_size = ffurl_size(c->inner);
+ h->is_streamed = c->inner->is_streamed;
+
+ ret = pthread_mutex_init(&c->mutex, NULL);
+ if (ret != 0) {
+ av_log(h, AV_LOG_ERROR, "pthread_mutex_init failed : %s\n", strerror(ret));
+ goto mutex_fail;
+ }
+
+ ret = pthread_cond_init(&c->cond_wakeup_main, NULL);
+ if (ret != 0) {
+ av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
+ goto cond_wakeup_main_fail;
+ }
+
+ ret = pthread_cond_init(&c->cond_wakeup_background, NULL);
+ if (ret != 0) {
+ av_log(h, AV_LOG_ERROR, "pthread_cond_init failed : %s\n", strerror(ret));
+ goto cond_wakeup_background_fail;
+ }
+
+ ret = pthread_create(&c->async_buffer_thread, NULL, async_buffer_task, h);
+ if (ret) {
+ av_log(h, AV_LOG_ERROR, "pthread_create failed : %s\n", strerror(ret));
+ goto thread_fail;
+ }
+
+ return 0;
+
+thread_fail:
+ pthread_cond_destroy(&c->cond_wakeup_background);
+cond_wakeup_background_fail:
+ pthread_cond_destroy(&c->cond_wakeup_main);
+cond_wakeup_main_fail:
+ pthread_mutex_destroy(&c->mutex);
+mutex_fail:
+ ffurl_close(c->inner);
+url_fail:
+ av_fifo_freep(&c->fifo);
+fifo_fail:
+ return ret;
+}
+
+static int async_close(URLContext *h)
+{
+ Context *c = h->priv_data;
+ int ret;
+
+ pthread_mutex_lock(&c->mutex);
+ c->abort_request = 1;
+ pthread_cond_signal(&c->cond_wakeup_background);
+ pthread_mutex_unlock(&c->mutex);
+
+ ret = pthread_join(c->async_buffer_thread, NULL);
+ if (ret != 0)
+ av_log(h, AV_LOG_ERROR, "pthread_join(): %s\n", strerror(ret));
+
+ pthread_cond_destroy(&c->cond_wakeup_background);
+ pthread_cond_destroy(&c->cond_wakeup_main);
+ pthread_mutex_destroy(&c->mutex);
+ ffurl_close(c->inner);
+ av_fifo_freep(&c->fifo);
+
+ return 0;
+}
+
+static int async_read_internal(URLContext *h, void *dest, int size, int read_complete,
+ void (*func)(void*, void*, int))
+{
+ Context *c = h->priv_data;
+ AVFifoBuffer *fifo = c->fifo;
+ int to_read = size;
+ int ret = 0;
+
+ pthread_mutex_lock(&c->mutex);
+
+ while (to_read > 0) {
+ if (async_interrupt_callback(h)) {
+ ret = AVERROR_EXIT;
+ break;
+ }
+ int fifo_size = av_fifo_size(fifo);
+ int to_copy = FFMIN(to_read, fifo_size);
+ if (to_copy > 0) {
+ av_fifo_generic_read(fifo, dest, to_copy, func);
+ if (!func)
+ dest = (uint8_t *)dest + to_copy;
+ c->logical_pos += to_copy;
+ to_read -= to_copy;
+ ret = size - to_read;
+
+ if (to_read <= 0 || !read_complete)
+ break;
+ } else if (c->io_eof_reached) {
+ if (ret <= 0)
+ ret = AVERROR_EOF;
+ break;
+ }
+ pthread_cond_signal(&c->cond_wakeup_background);
+ pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
+ }
+
+ pthread_cond_signal(&c->cond_wakeup_background);
+ pthread_mutex_unlock(&c->mutex);
+
+ return ret;
+}
+
+static int async_read(URLContext *h, unsigned char *buf, int size)
+{
+ return async_read_internal(h, buf, size, 0, NULL);
+}
+
+static void fifo_do_not_copy_func(void* dest, void* src, int size) {
+ // do not copy
+}
+
+static int64_t async_seek(URLContext *h, int64_t pos, int whence)
+{
+ Context *c = h->priv_data;
+ AVFifoBuffer *fifo = c->fifo;
+ int64_t ret;
+ int64_t new_logical_pos;
+
+ if (whence == AVSEEK_SIZE) {
+ av_log(h, AV_LOG_TRACE, "async_seek: AVSEEK_SIZE: %"PRId64"\n", (int64_t)c->logical_size);
+ return c->logical_size;
+ } if (whence == SEEK_CUR) {
+ av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
+ new_logical_pos = pos + c->logical_pos;
+ } else if (whence == SEEK_SET){
+ av_log(h, AV_LOG_TRACE, "async_seek: %"PRId64"\n", pos);
+ new_logical_pos = pos;
+ } else {
+ return AVERROR(EINVAL);
+ }
+ if (new_logical_pos < 0)
+ return AVERROR(EINVAL);
+
+ int fifo_size = av_fifo_size(fifo);
+ if (new_logical_pos == c->logical_pos) {
+ /* current position */
+ return c->logical_pos;
+ } else if ((new_logical_pos > c->logical_pos) &&
+ (new_logical_pos < (c->logical_pos + fifo_size + SHORT_SEEK_THRESHOLD))) {
+ /* fast seek */
+ av_log(h, AV_LOG_TRACE, "async_seek: fask_seek %"PRId64" from %d dist:%d/%d\n",
+ new_logical_pos, (int)c->logical_pos,
+ (int)(new_logical_pos - c->logical_pos), fifo_size);
+ async_read_internal(h, NULL, new_logical_pos - c->logical_pos, 1, fifo_do_not_copy_func);
+ return c->logical_pos;
+ } else if (c->logical_size <= 0) {
+ /* can not seek */
+ return AVERROR(EINVAL);
+ } else if (new_logical_pos > c->logical_size) {
+ /* beyond end */
+ return AVERROR(EINVAL);
+ }
+
+ pthread_mutex_lock(&c->mutex);
+
+ c->seek_request = 1;
+ c->seek_pos = new_logical_pos;
+ c->seek_whence = SEEK_SET;
+ c->seek_completed = 0;
+ c->seek_ret = 0;
+
+ while (1) {
+ if (async_interrupt_callback(h)) {
+ ret = AVERROR_EXIT;
+ break;
+ }
+ if (c->seek_completed) {
+ if (c->seek_ret >= 0)
+ c->logical_pos = c->seek_ret;
+ ret = c->seek_ret;
+ break;
+ }
+ pthread_cond_signal(&c->cond_wakeup_background);
+ pthread_cond_wait(&c->cond_wakeup_main, &c->mutex);
+ }
+
+ pthread_mutex_unlock(&c->mutex);
+
+ return ret;
+}
+
+#define OFFSET(x) offsetof(Context, x)
+#define D AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+ {NULL},
+};
+
+static const AVClass async_context_class = {
+ .class_name = "Async",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+URLProtocol ff_async_protocol = {
+ .name = "async",
+ .url_open2 = async_open,
+ .url_read = async_read,
+ .url_seek = async_seek,
+ .url_close = async_close,
+ .priv_data_size = sizeof(Context),
+ .priv_data_class = &async_context_class,
+};
--
2.0.0
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