[FFmpeg-devel] [PATCH 4/4] examples: adding device_get_capabilities example

Diederick Niehorster dcnieho at gmail.com
Fri Jun 4 01:45:52 EEST 2021


Signed-off-by: Diederick Niehorster <dcnieho at gmail.com>
---
 configure                              |   2 +
 doc/examples/.gitignore                |   1 +
 doc/examples/Makefile                  |  47 ++++----
 doc/examples/Makefile.example          |   1 +
 doc/examples/device_get_capabilities.c | 151 +++++++++++++++++++++++++
 5 files changed, 179 insertions(+), 23 deletions(-)
 create mode 100644 doc/examples/device_get_capabilities.c

diff --git a/configure b/configure
index 82367fd30d..5e9666d017 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..7988ed4226 100644
--- a/doc/examples/Makefile
+++ b/doc/examples/Makefile
@@ -1,26 +1,27 @@
-EXAMPLES-$(CONFIG_AVIO_LIST_DIR_EXAMPLE)     += avio_list_dir
-EXAMPLES-$(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_ENCODE_AUDIO_EXAMPLE)      += encode_audio
-EXAMPLES-$(CONFIG_ENCODE_VIDEO_EXAMPLE)      += encode_video
-EXAMPLES-$(CONFIG_EXTRACT_MVS_EXAMPLE)       += extract_mvs
-EXAMPLES-$(CONFIG_FILTER_AUDIO_EXAMPLE)      += filter_audio
-EXAMPLES-$(CONFIG_FILTERING_AUDIO_EXAMPLE)   += filtering_audio
-EXAMPLES-$(CONFIG_FILTERING_VIDEO_EXAMPLE)   += filtering_video
-EXAMPLES-$(CONFIG_HTTP_MULTICLIENT_EXAMPLE)  += http_multiclient
-EXAMPLES-$(CONFIG_HW_DECODE_EXAMPLE)         += hw_decode
-EXAMPLES-$(CONFIG_METADATA_EXAMPLE)          += metadata
-EXAMPLES-$(CONFIG_MUXING_EXAMPLE)            += muxing
-EXAMPLES-$(CONFIG_QSVDEC_EXAMPLE)            += qsvdec
-EXAMPLES-$(CONFIG_REMUXING_EXAMPLE)          += remuxing
-EXAMPLES-$(CONFIG_RESAMPLING_AUDIO_EXAMPLE)  += resampling_audio
-EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE)     += scaling_video
-EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE)     += transcode_aac
-EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE)       += transcoding
-EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE)      += vaapi_encode
-EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE)   += vaapi_transcode
+EXAMPLES-$(CONFIG_AVIO_LIST_DIR_EXAMPLE)             += avio_list_dir
+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
+EXAMPLES-$(CONFIG_FILTER_AUDIO_EXAMPLE)              += filter_audio
+EXAMPLES-$(CONFIG_FILTERING_AUDIO_EXAMPLE)           += filtering_audio
+EXAMPLES-$(CONFIG_FILTERING_VIDEO_EXAMPLE)           += filtering_video
+EXAMPLES-$(CONFIG_HTTP_MULTICLIENT_EXAMPLE)          += http_multiclient
+EXAMPLES-$(CONFIG_HW_DECODE_EXAMPLE)                 += hw_decode
+EXAMPLES-$(CONFIG_METADATA_EXAMPLE)                  += metadata
+EXAMPLES-$(CONFIG_MUXING_EXAMPLE)                    += muxing
+EXAMPLES-$(CONFIG_QSVDEC_EXAMPLE)                    += qsvdec
+EXAMPLES-$(CONFIG_REMUXING_EXAMPLE)                  += remuxing
+EXAMPLES-$(CONFIG_RESAMPLING_AUDIO_EXAMPLE)          += resampling_audio
+EXAMPLES-$(CONFIG_SCALING_VIDEO_EXAMPLE)             += scaling_video
+EXAMPLES-$(CONFIG_TRANSCODE_AAC_EXAMPLE)             += transcode_aac
+EXAMPLES-$(CONFIG_TRANSCODING_EXAMPLE)               += transcoding
+EXAMPLES-$(CONFIG_VAAPI_ENCODE_EXAMPLE)              += vaapi_encode
+EXAMPLES-$(CONFIG_VAAPI_TRANSCODE_EXAMPLE)           += vaapi_transcode
 
 EXAMPLES       := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)$(EXESUF))
 EXAMPLES_G     := $(EXAMPLES-yes:%=doc/examples/%$(PROGSSUF)_g$(EXESUF))
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..f3b9f31e0d
--- /dev/null
+++ b/doc/examples/device_get_capabilities.c
@@ -0,0 +1,151 @@
+/*
+ * 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>
+
+
+
+int main (int argc, char **argv)
+{
+    int ret = 0;
+    const char* dshow_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;
+
+    if (argc != 5) {
+        fprintf(stderr, "usage: %s  dshow_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 video=\"Integrated Webcam\" frame_size pixel_format yuyv422",
+                argv[0], argv[0]);
+        exit(1);
+    }
+    dshow_input_name = argv[1];
+    query_cap = argv[2];
+    set_cap_name = argv[3];
+    set_cap_value = argv[4];
+
+    // make sure avdevices can be found
+    avdevice_register_all();
+    // find our device (capabilities API is currently
+    // only implemented for dshow device, so hardcode that)
+    fmt = av_find_input_format("dshow");
+
+    // since there is no equivalent of avformat_alloc_output_context2 for an input context,
+    // so we get this dirty code that users shouldn't have to write....
+    fmt_ctx = avformat_alloc_context();
+    fmt_ctx->url = av_strdup(dshow_input_name);
+    fmt_ctx->iformat = fmt;
+    if (fmt_ctx->iformat->priv_data_size > 0) {
+        if (!(fmt_ctx->priv_data = av_mallocz(fmt_ctx->iformat->priv_data_size))) {
+            ret = AVERROR(ENOMEM);
+            goto end;
+        }
+        if (fmt_ctx->iformat->priv_class) {
+            *(const AVClass**)fmt_ctx->priv_data = fmt_ctx->iformat->priv_class;
+            av_opt_set_defaults(fmt_ctx->priv_data);
+        }
+    }
+    // end dirty code
+
+    // query the capability without any filter set
+    ret = avdevice_capabilities_create(&caps, fmt_ctx, NULL);
+    if (ret < 0)
+        goto end;
+
+    ret = av_opt_query_ranges(&ranges, caps, query_cap, AV_OPT_MULTI_COMPONENT_RANGE);
+    if (ret < 0)
+        goto end;
+
+    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: %.2f -- %.2f", range->str, range->value_min, range->value_max);
+        }
+        printf("\n");
+    }
+    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)
+        goto end;
+
+    ret = av_opt_query_ranges(&ranges, caps, query_cap, AV_OPT_MULTI_COMPONENT_RANGE);
+    if (ret < 0)
+        goto end;
+
+    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: %.2f -- %.2f", range->str, range->value_min, range->value_max);
+        }
+        printf("\n");
+    }
+
+
+end:
+    av_opt_freep_ranges(&ranges);
+    avdevice_capabilities_free(&caps, fmt_ctx);
+
+    avformat_close_input(&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;
+}
-- 
2.28.0.windows.1



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