diff mbox series

[FFmpeg-devel,v2,30/33] doc/examples: adding device_get_capabilities example

Message ID 20210611203104.1692-31-dcnieho@gmail.com
State Superseded, archived
Headers show
Series avdevice (mostly dshow) enhancements
Related show

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Commit Message

Diederick C. Niehorster June 11, 2021, 8:31 p.m. UTC
Signed-off-by: Diederick Niehorster <dcnieho@gmail.com>
---
 configure                              |   2 +
 doc/examples/.gitignore                |   1 +
 doc/examples/Makefile                  |   1 +
 doc/examples/Makefile.example          |   1 +
 doc/examples/device_get_capabilities.c | 190 +++++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 doc/examples/device_get_capabilities.c
diff mbox series

Patch

diff --git a/configure b/configure
index 6bfd98b384..31b1790c8d 100755
--- a/configure
+++ b/configure
@@ -1705,6 +1705,7 @@  EXAMPLE_LIST="
     decode_audio_example
     decode_video_example
     demuxing_decoding_example
+    device_get_capabilities_example
     encode_audio_example
     encode_video_example
     extract_mvs_example
@@ -3712,6 +3713,7 @@  avio_reading_deps="avformat avcodec avutil"
 decode_audio_example_deps="avcodec avutil"
 decode_video_example_deps="avcodec avutil"
 demuxing_decoding_example_deps="avcodec avformat avutil"
+device_get_capabilities_example_deps="avdevice avformat avutil"
 encode_audio_example_deps="avcodec avutil"
 encode_video_example_deps="avcodec avutil"
 extract_mvs_example_deps="avcodec avformat avutil"
diff --git a/doc/examples/.gitignore b/doc/examples/.gitignore
index 44960e1de7..256f33a600 100644
--- a/doc/examples/.gitignore
+++ b/doc/examples/.gitignore
@@ -3,6 +3,7 @@ 
 /decode_audio
 /decode_video
 /demuxing_decoding
+/device_get_capabilities
 /encode_audio
 /encode_video
 /extract_mvs
diff --git a/doc/examples/Makefile b/doc/examples/Makefile
index 81bfd34d5d..de707bb3ca 100644
--- a/doc/examples/Makefile
+++ b/doc/examples/Makefile
@@ -3,6 +3,7 @@  EXAMPLES-$(CONFIG_AVIO_READING_EXAMPLE)      += avio_reading
 EXAMPLES-$(CONFIG_DECODE_AUDIO_EXAMPLE)      += decode_audio
 EXAMPLES-$(CONFIG_DECODE_VIDEO_EXAMPLE)      += decode_video
 EXAMPLES-$(CONFIG_DEMUXING_DECODING_EXAMPLE) += demuxing_decoding
+EXAMPLES-$(CONFIG_DEVICE_GET_CAPABILITIES_EXAMPLE) += device_get_capabilities
 EXAMPLES-$(CONFIG_ENCODE_AUDIO_EXAMPLE)      += encode_audio
 EXAMPLES-$(CONFIG_ENCODE_VIDEO_EXAMPLE)      += encode_video
 EXAMPLES-$(CONFIG_EXTRACT_MVS_EXAMPLE)       += extract_mvs
diff --git a/doc/examples/Makefile.example b/doc/examples/Makefile.example
index a232d97f98..b861b9cc74 100644
--- a/doc/examples/Makefile.example
+++ b/doc/examples/Makefile.example
@@ -16,6 +16,7 @@  EXAMPLES=       avio_list_dir                      \
                 decode_audio                       \
                 decode_video                       \
                 demuxing_decoding                  \
+                device_get_capabilities            \
                 encode_audio                       \
                 encode_video                       \
                 extract_mvs                        \
diff --git a/doc/examples/device_get_capabilities.c b/doc/examples/device_get_capabilities.c
new file mode 100644
index 0000000000..46a7d1a86f
--- /dev/null
+++ b/doc/examples/device_get_capabilities.c
@@ -0,0 +1,190 @@ 
+/*
+ * Copyright (c) 2021 Diederick Niehorster
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * @file
+ * avdevice getting capabilities example.
+ *
+ * Shows how to use the avdevice capabilities API to probe
+ * device capabilities (supported codecs, pixel formats, sample
+ * formats, resolutions, channel counts, etc)
+ * @example device_get_capabilities.c
+ */
+
+#include <libavdevice/avdevice.h>
+#include <libavutil/avstring.h>
+#include <libavformat/avformat.h>
+#include <libavutil/log.h>
+
+void print_option_ranges(enum AVOptionType type, AVOptionRanges* ranges)
+{
+    for (int range_index = 0; range_index < ranges->nb_ranges; range_index++) {
+        for (int component_index = 0; component_index < ranges->nb_components; component_index++)
+        {
+            AVOptionRange* range = ranges->range[ranges->nb_ranges * component_index + range_index];
+            if (component_index > 0)
+                printf(", ");
+            printf("%s: ", range->str);
+            if (range->value_min > range->value_max) {
+                printf("<value not available>");
+            } else {
+                uint8_t* buf;
+                if (av_opt_print_num(type, range->value_min, &buf) < 0)
+                    // fallback to just printing value
+                    printf("%.2f", range->value_min);
+                else {
+                    printf("%s", (const char*)buf);
+                    av_freep(&buf);
+                }
+                if (range->is_range) {
+                    if (av_opt_print_num(type, range->value_max, &buf) < 0)
+                        // fallback to just printing value
+                        printf(" -- %.2f", range->value_max);
+                    else {
+                        printf(" -- %s", (const char*)buf);
+                        av_freep(&buf);
+                    }
+                }
+            }
+        }
+        printf("\n");
+    }
+}
+
+
+
+int main (int argc, char **argv)
+{
+    int ret = 0;
+    const char* device_name = NULL;
+    const char* input_name = NULL;
+    const char* query_cap = NULL;
+    const char* set_cap_name = NULL;
+    const char* set_cap_value = NULL;
+
+    const AVInputFormat* fmt = NULL;
+    AVFormatContext* fmt_ctx = NULL;
+    AVDeviceCapabilitiesQuery* caps = NULL;
+    AVOptionRanges* ranges = NULL;
+    AVDictionary* options = NULL;
+    const AVOption* opt = NULL;
+
+    if (argc != 6) {
+        fprintf(stderr, "usage: %s  device_name input_name query_cap set_cap_name set_cap_value\n"
+                "API example program to show how to use the avdevice\n"
+                "capabilities API to probe device capabilities \n"
+                "(supported codecs, pixel formats, sample formats,\n"
+                "resolutions, channel counts, etc).\n\n"
+                "example invocation: "
+                "%s dshow video=\"Integrated Webcam\" frame_size pixel_format yuyv422",
+                argv[0], argv[0]);
+        exit(1);
+    }
+    device_name = argv[1];
+    input_name = argv[2];
+    query_cap = argv[3];
+    set_cap_name = argv[4];
+    set_cap_value = argv[5];
+
+    // make sure avdevices can be found among input and output formats
+    avdevice_register_all();
+    // find specified device
+    fmt = av_find_input_format(device_name);
+    if (!fmt) {
+        fprintf(stderr, "Could not find the device '%s'\n",device_name);
+        ret = AVERROR(EINVAL);
+        goto end;
+    }
+
+    // prepare device format context, and set device to query, 
+    ret = avformat_alloc_input_context(&fmt_ctx, fmt, NULL);
+    if (ret < 0) {
+        fprintf(stderr, "Cannot allocate input format context\n");
+        goto end;
+    }
+    fmt_ctx->url = av_strdup("video=Integrated Webcam:audio=OBS-Audio");
+
+    // prepare query object, setting device options (if any)
+    ret = avdevice_capabilities_create(&caps, fmt_ctx, &options);
+    if (ret < 0) {
+        fprintf(stderr, "avdevice_capabilities_create() failed\n");
+        goto end;
+    }
+
+    // check capability to query, and get info about the return type
+    opt = av_opt_find(caps, query_cap, NULL, 0, 0);
+    if (!opt) {
+        fprintf(stderr, "Capability '%s' you wish to query is not available\n", query_cap);
+        ret = AVERROR_OPTION_NOT_FOUND;
+        goto end;
+    }
+
+    // query the capability without any filter set
+    ret = av_opt_query_ranges(&ranges, caps, opt->name, AV_OPT_MULTI_COMPONENT_RANGE);
+    if (ret < 0) {
+        fprintf(stderr, "av_opt_query_ranges() failed\n");
+        goto end;
+    }
+
+    // print results
+    print_option_ranges(opt->type, ranges);
+    av_opt_freep_ranges(&ranges);
+
+    printf("=============\n");
+
+    // set one capability, which may filter out some returned capabilities
+    // (or all, if set to an invalid value)
+    ret = av_opt_set(caps, set_cap_name, set_cap_value, 0);
+    if (ret < 0) {
+        fprintf(stderr, "av_opt_set() failed\n");
+        goto end;
+    }
+
+    // query again
+    ret = av_opt_query_ranges(&ranges, caps, opt->name, AV_OPT_MULTI_COMPONENT_RANGE);
+    if (ret < 0) {
+        fprintf(stderr, "av_opt_query_ranges() failed\n");
+        goto end;
+    }
+
+    // print results
+    print_option_ranges(opt->type, ranges);
+
+
+end:
+    if (ranges)
+        av_opt_freep_ranges(&ranges);
+    if (caps)
+        avdevice_capabilities_free(&caps, fmt_ctx);
+
+    if (fmt_ctx)
+        avformat_free_context(fmt_ctx);
+
+    if (ret < 0) {
+        char a[AV_ERROR_MAX_STRING_SIZE] = { 0 };
+        av_make_error_string(a, AV_ERROR_MAX_STRING_SIZE, ret);
+
+        printf("Error: %s\n", a);
+    }
+
+    return ret < 0;
+}