[FFmpeg-devel] [PATCH v2] libavformat: Add ZeroMQ as a protocol option
Andriy Gelman
andriy.gelman at gmail.com
Wed Aug 7 05:15:01 EEST 2019
On Sun, 04. Aug 14:36, Andriy Gelman wrote:
> Changes in v2:
> 1. Replaced zmq_poll with zmq_msg_recv.
> 2. Remove user timeout option as zmq_msg_recv(.., .., ZMQ_DONTWAIT) is a
> non-blocking call.
> 3. Updated docs.
>
> Andriy
>
> From 53e6e00d30c9fbf5127eea9d377686d37e981c0c Mon Sep 17 00:00:00 2001
> From: Andriy Gelman <andriy.gelman at gmail.com>
> Date: Tue, 30 Jul 2019 14:39:32 -0400
> Subject: [PATCH] libavformat: Add ZeroMQ as a protocol option
>
> Currently multiple clients are only supported by using a
> multicast destination address. An alternative is to stream to a server
> which re-distributes the content.
>
> This commit adds ZeroMQ as a protocol option, which allows
> multiple clients to connect to a single ffmpeg instance.
> ---
> configure | 2 +
> doc/general.texi | 1 +
> doc/protocols.texi | 32 ++++++++
> libavformat/Makefile | 1 +
> libavformat/libzmq.c | 159 ++++++++++++++++++++++++++++++++++++++++
> libavformat/protocols.c | 1 +
> 6 files changed, 196 insertions(+)
> create mode 100644 libavformat/libzmq.c
>
> diff --git a/configure b/configure
> index 5a4f507246..4515341b06 100755
> --- a/configure
> +++ b/configure
> @@ -3400,6 +3400,8 @@ libsrt_protocol_deps="libsrt"
> libsrt_protocol_select="network"
> libssh_protocol_deps="libssh"
> libtls_conflict="openssl gnutls mbedtls"
> +libzmq_protocol_deps="libzmq"
> +libzmq_protocol_select="network"
>
> # filters
> afftdn_filter_deps="avcodec"
> diff --git a/doc/general.texi b/doc/general.texi
> index 3c0c803449..b8e063268c 100644
> --- a/doc/general.texi
> +++ b/doc/general.texi
> @@ -1329,6 +1329,7 @@ performance on systems without hardware floating point support).
> @item TCP @tab X
> @item TLS @tab X
> @item UDP @tab X
> + at item ZMQ @tab E
> @end multitable
>
> @code{X} means that the protocol is supported.
> diff --git a/doc/protocols.texi b/doc/protocols.texi
> index 3e4e7af3d4..174eaacd0f 100644
> --- a/doc/protocols.texi
> +++ b/doc/protocols.texi
> @@ -1728,4 +1728,36 @@ Timeout in ms.
> Create the Unix socket in listening mode.
> @end table
>
> + at section libzmq
> +
> +ZeroMQ asynchronous messaging library.
> +
> +This library supports unicast streaming to multiple clients without relying on
> +an external server.
> +
> +The required syntax for streaming or connecting to a stream is:
> + at example
> +zmq:tcp://ip-address:port
> + at end example
> +
> +Example:
> +Create a localhost stream on port 5555:
> + at example
> +ffmpeg -re -i input -f mpegts zmq:tcp://127.0.0.1:5555
> + at end example
> +
> +Multiple clients may connect to the stream using:
> + at example
> +ffplay zmq:tcp://127.0.0.1:5555
> + at end example
> +
> +Streaming to multiple clients is implemented using a ZMQ Pub-Sub pattern.
> +The server binds to a port and publishes data. Clients connect to the
> +server (IP address/port) and subscribe to the stream. The order in which
> +the server and client start generally does not matter.
> +
> +ffmpeg must be compiled with the --enable-libzmq option to support
> +this protocol option. See the compilation guide @url{https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu}
> +for an example on how this option may be set.
> +
> @c man end PROTOCOLS
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index a434b005a4..4a535429b7 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -631,6 +631,7 @@ OBJS-$(CONFIG_LIBRTMPTE_PROTOCOL) += librtmp.o
> OBJS-$(CONFIG_LIBSMBCLIENT_PROTOCOL) += libsmbclient.o
> OBJS-$(CONFIG_LIBSRT_PROTOCOL) += libsrt.o
> OBJS-$(CONFIG_LIBSSH_PROTOCOL) += libssh.o
> +OBJS-$(CONFIG_LIBZMQ_PROTOCOL) += libzmq.o
>
> # libavdevice dependencies
> OBJS-$(CONFIG_IEC61883_INDEV) += dv.o
> diff --git a/libavformat/libzmq.c b/libavformat/libzmq.c
> new file mode 100644
> index 0000000000..24eebb1fee
> --- /dev/null
> +++ b/libavformat/libzmq.c
> @@ -0,0 +1,159 @@
> +/*
> + * ZMQ URLProtocol
> + *
> + * 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 <zmq.h>
> +#include "url.h"
> +#include "network.h"
> +#include "libavutil/avstring.h"
> +#include "libavutil/opt.h"
> +
> +typedef struct ZMQContext {
> + const AVClass *class;
> + void *context;
> + void *socket;
> + unsigned int timeout; /*blocking timeout during zmq poll in milliseconds */
> +} ZMQContext;
> +
> +static const AVOption options[] = {
> + { NULL }
> +};
> +
> +static int ff_zmq_open(URLContext *h, const char *uri, int flags)
> +{
> + int ret;
> + ZMQContext *s = h->priv_data;
> + s->context = zmq_ctx_new();
> + h->is_streamed = 1;
> +
> + av_strstart(uri, "zmq:", &uri);
> +
> + /*publish during write*/
> + if (h->flags & AVIO_FLAG_WRITE) {
> + s->socket = zmq_socket(s->context, ZMQ_PUB);
> + if (!s->socket) {
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_socket(): %s\n", zmq_strerror(errno));
> + zmq_ctx_destroy(s->context);
> + return AVERROR_EXTERNAL;
> + }
> +
> + ret = zmq_bind(s->socket, uri);
> + if (ret < 0) {
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_bind(): %s\n", zmq_strerror(errno));
> + zmq_close(s->socket);
> + zmq_ctx_destroy(s->context);
> + return AVERROR_EXTERNAL;
> + }
> + }
> +
> + /*subscribe for read*/
> + if (h->flags & AVIO_FLAG_READ) {
> + s->socket = zmq_socket(s->context, ZMQ_SUB);
> + if (!s->socket) {
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_socket(): %s\n", zmq_strerror(errno));
> + zmq_ctx_destroy(s->context);
> + return AVERROR_EXTERNAL;
> + }
> +
> + zmq_setsockopt(s->socket, ZMQ_SUBSCRIBE, "", 0);
> + ret = zmq_connect(s->socket, uri);
> + if (ret == -1) {
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_connect(): %s\n", zmq_strerror(errno));
> + zmq_close(s->socket);
> + zmq_ctx_destroy(s->context);
> + return AVERROR_EXTERNAL;
> + }
> + }
> + return 0;
> +}
> +
> +static int ff_zmq_write(URLContext *h, const unsigned char *buf, int size)
> +{
> + int ret;
> + ZMQContext *s = h->priv_data;
> +
> + ret = zmq_send(s->socket, buf, size, ZMQ_DONTWAIT);
> + if (ret >= 0)
> + return ret; /*number of sent bytes*/
> +
> + /*errno = EAGAIN if messages cannot be pushed*/
> + if (ret == -1 && errno == EAGAIN) {
> + return AVERROR(EAGAIN);
> + } else
> + return AVERROR_EXTERNAL;
> +}
> +
> +static int ff_zmq_read(URLContext *h, unsigned char *buf, int size)
> +{
> + int ret;
> + ZMQContext *s = h->priv_data;
> + zmq_msg_t msg;
> + int msg_size;
> +
> + ret = zmq_msg_init(&msg);
> + if (ret == -1) {
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_msg_init(): %s\n", zmq_strerror(errno));
> + return AVERROR_EXTERNAL;
> + }
> +
> + ret = zmq_msg_recv(&msg, s->socket, ZMQ_DONTWAIT);
> + if (ret == -1) {
> + ret = (errno == EAGAIN) ? AVERROR(EAGAIN) : AVERROR_EXTERNAL;
> + if (ret == AVERROR_EXTERNAL)
> + av_log(h, AV_LOG_ERROR, "Error occured during zmq_msg_recv(): %s\n", zmq_strerror(errno));
> + goto finish;
> + }
> +
> + msg_size = zmq_msg_size(&msg);
> + if (msg_size > size) {
> + msg_size = size;
> + av_log(h, AV_LOG_WARNING, "ZMQ message exceeds available space in the buffer. Message will be truncated\n");
> + }
> + memcpy(buf, zmq_msg_data(&msg), msg_size);
> +
> +finish:
> + zmq_msg_close(&msg);
> + return ret;
> +}
> +
> +static int ff_zmq_close(URLContext *h)
> +{
> + ZMQContext *s = h->priv_data;
> + zmq_close(s->socket);
> + zmq_ctx_destroy(s->context);
> + return 0;
> +}
> +
> +static const AVClass zmq_context_class = {
> + .class_name = "zmq",
> + .item_name = av_default_item_name,
> + .option = options,
> + .version = LIBAVUTIL_VERSION_INT,
> +};
> +
> +const URLProtocol ff_libzmq_protocol = {
> + .name = "zmq",
> + .url_close = ff_zmq_close,
> + .url_open = ff_zmq_open,
> + .url_read = ff_zmq_read,
> + .url_write = ff_zmq_write,
> + .priv_data_size = sizeof(ZMQContext),
> + .priv_data_class = &zmq_context_class,
> + .flags = URL_PROTOCOL_FLAG_NETWORK,
> +};
> diff --git a/libavformat/protocols.c b/libavformat/protocols.c
> index ad95659795..face5b29b5 100644
> --- a/libavformat/protocols.c
> +++ b/libavformat/protocols.c
> @@ -68,6 +68,7 @@ extern const URLProtocol ff_librtmpte_protocol;
> extern const URLProtocol ff_libsrt_protocol;
> extern const URLProtocol ff_libssh_protocol;
> extern const URLProtocol ff_libsmbclient_protocol;
> +extern const URLProtocol ff_libzmq_protocol;
>
> #include "libavformat/protocol_list.c"
>
> --
> 2.22.0
ping
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