Minimalistic capture device sampling textual data from a character
device. Part I
---
libavdevice/Makefile | 1 +
libavdevice/alldevices.c | 1 +
libavdevice/rawdata.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 133 insertions(+), 0 deletions(-)
create mode 100644 libavdevice/rawdata.c
diff --git a/libavdevice/Makefile b/libavdevice/Makefile
index 76d11c1..e716ac8 100644
--- a/libavdevice/Makefile
+++ b/libavdevice/Makefile
@@ -19,6 +19,7 @@ OBJS-$(CONFIG_JACK_INDEV) += jack_audio.o
timefilter.o
OBJS-$(CONFIG_OSS_INDEV) += oss_audio.o
OBJS-$(CONFIG_OSS_OUTDEV) += oss_audio.o
OBJS-$(CONFIG_PULSE_INDEV) += pulse.o
+OBJS-$(CONFIG_RAWDATA_INDEV) += rawdata.o
OBJS-$(CONFIG_SNDIO_INDEV) += sndio_common.o sndio_dec.o
OBJS-$(CONFIG_SNDIO_OUTDEV) += sndio_common.o sndio_enc.o
OBJS-$(CONFIG_V4L2_INDEV) += v4l2.o
diff --git a/libavdevice/alldevices.c b/libavdevice/alldevices.c
index 9ec9fdf..5343190 100644
--- a/libavdevice/alldevices.c
+++ b/libavdevice/alldevices.c
@@ -46,6 +46,7 @@ void avdevice_register_all(void)
REGISTER_INDEV (JACK, jack);
REGISTER_INOUTDEV (OSS, oss);
REGISTER_INDEV (PULSE, pulse);
+ REGISTER_INDEV (RAWDATA, rawdata);
REGISTER_INOUTDEV (SNDIO, sndio);
REGISTER_INDEV (V4L2, v4l2);
REGISTER_INDEV (VFWCAP, vfwcap);
diff --git a/libavdevice/rawdata.c b/libavdevice/rawdata.c
new file mode 100644
index 0000000..f08bf24
--- /dev/null
+++ b/libavdevice/rawdata.c
@@ -0,0 +1,131 @@
+/*
+ * Raw data input
+ * Copyright (c) 2011 Luca Barbato <[email protected]>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Generate a data stream by sampling a character device.
+ * @author Luca Barbato <[email protected]>
+ */
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "libavformat/avformat.h"
+#include "libavformat/internal.h"
+#include "libavutil/opt.h"
+
+typedef struct {
+ AVClass *class;
+ int threading;
+ int timeout;
+ int size;
+ int64_t start_time;
+ int64_t pts;
+ int fd;
+} RawData;
+
+
+static int rawdata_read_header(AVFormatContext *s)
+{
+ RawData *rd = s->priv_data;
+ AVStream *st = avformat_new_stream(s, NULL);
+
+ st->codec->codec_type = AVMEDIA_TYPE_DATA;
+ st->codec->codec_id = AV_CODEC_ID_TEXT;
+ avpriv_set_pts_info(st, 64, 1, 1000000);
+
+ rd->fd = open(s->filename, O_RDWR | O_NONBLOCK, 0);
+
+ if (rd->fd < 0) {
+ int err = errno;
+
+ av_log(s, AV_LOG_ERROR, "Cannot open video device %s : %s\n",
+ s->filename, strerror(err));
+
+ return AVERROR(err);
+ }
+
+ return 0;
+}
+
+static int rawdata_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ RawData *rd = s->priv_data;
+ int res;
+
+ if (av_new_packet(pkt, rd->size) < 0) {
+ return AVERROR(ENOMEM);
+ }
+
+ res = read(rd->fd, pkt->data, rd->size);
+
+ if (rd->pts == AV_NOPTS_VALUE) {
+ rd->pts = av_gettime() - rd->start_time;
+ pkt->pts = rd->start_time;
+ } else {
+ rd->pts = pkt->pts = av_gettime() - rd->pts;
+ }
+
+ if (res < rd->size) {
+ av_free_packet(pkt);
+ return AVERROR(EAGAIN);
+ }
+
+ return 0;
+}
+
+static av_cold int rawdata_close(AVFormatContext *s)
+{
+ RawData *rd = s->priv_data;
+ close(rd->fd);
+ return 0;
+}
+
+#define OFFSET(a) offsetof(RawData, a)
+#define D AV_OPT_FLAG_DECODING_PARAM
+
+static const AVOption options[] = {
+ { "timeout", "poll time in milliseconds", OFFSET(timeout),
AV_OPT_TYPE_INT, {.i64 = 100}, -1, INT_MAX, D },
+ { "threaded", "use a polling thread", OFFSET(threading),
AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, D },
+ { "size", "amount of data to be stored in a packet",
OFFSET(size), AV_OPT_TYPE_INT, {.i64 = 128}, 1, INT_MAX, D },
+ { "start_time", "initial time in milliseconds", OFFSET(size),
AV_OPT_TYPE_INT64, {.i64 = 0}, 0, INT64_MAX, D },
+};
+
+static const AVClass rawdata_demuxer_class = {
+ .class_name = "Textdata reader",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_rawdata_demuxer = {
+ .name = "rawdata",
+ .long_name = NULL_IF_CONFIG_SMALL("Raw rawdata input"),
+ .priv_data_size = sizeof(RawData),
+ .read_header = rawdata_read_header,
+ .read_packet = rawdata_read_packet,
+ .read_close = rawdata_close,
+ .flags = AVFMT_NOFILE,
+ .priv_class = &rawdata_demuxer_class,
+};
+
--
1.7.8.rc1
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