[FFmpeg-devel,v3,24/25] doc/examples/extract_timed_metadata: added a bare-bones metadata extractor; find only the frames

Submitted by erkki.seppala.ext@nokia.com on Sept. 19, 2016, 1:25 p.m.

Details

Message ID 1474291548-17810-25-git-send-email-erkki.seppala.ext@nokia.com
State New
Headers show

Commit Message

erkki.seppala.ext@nokia.com Sept. 19, 2016, 1:25 p.m.
Signed-off-by: Erkki Seppälä <erkki.seppala.ext@nokia.com>
Signed-off-by: OZOPlayer <OZOPL@nokia.com>
---
 configure                             |   2 +
 doc/examples/Makefile                 |   1 +
 doc/examples/extract_timed_metadata.c | 230 ++++++++++++++++++++++++++++++++++
 3 files changed, 233 insertions(+)
 create mode 100644 doc/examples/extract_timed_metadata.c

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diff --git a/configure b/configure
index ded5452..b586353 100755
--- a/configure
+++ b/configure
@@ -1453,6 +1453,7 @@  EXAMPLE_LIST="
     decoding_encoding_example
     demuxing_decoding_example
     extract_mvs_example
+    extract_timed_metadata_example
     filter_audio_example
     filtering_audio_example
     filtering_video_example
@@ -3088,6 +3089,7 @@  avio_reading="avformat avcodec avutil"
 decoding_encoding_example_deps="avcodec avformat avutil"
 demuxing_decoding_example_deps="avcodec avformat avutil"
 extract_mvs_example_deps="avcodec avformat avutil"
+extract_timed_metadata_example_deps="avcodec avformat avutil"
 filter_audio_example_deps="avfilter avutil"
 filtering_audio_example_deps="avfilter avcodec avformat avutil"
 filtering_video_example_deps="avfilter avcodec avformat avutil"
diff --git a/doc/examples/Makefile b/doc/examples/Makefile
index af38159..c10033e 100644
--- a/doc/examples/Makefile
+++ b/doc/examples/Makefile
@@ -16,6 +16,7 @@  EXAMPLES=       avio_dir_cmd                       \
                 decoding_encoding                  \
                 demuxing_decoding                  \
                 extract_mvs                        \
+                extract_timed_metadata             \
                 filtering_video                    \
                 filtering_audio                    \
                 http_multiclient                   \
diff --git a/doc/examples/extract_timed_metadata.c b/doc/examples/extract_timed_metadata.c
new file mode 100644
index 0000000..51de6bd
--- /dev/null
+++ b/doc/examples/extract_timed_metadata.c
@@ -0,0 +1,230 @@ 
+/*
+ * Copyright (c) 2010 Nicolas George
+ * Copyright (c) 2011 Stefano Sabatini
+ * Copyright (c) 2015 Erkki Seppälä <erkki.seppala.ext@nokia.com>
+ *
+ * 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
+ * API example extracting timed metadata
+ * @example extract_timed_metadata.c
+ */
+
+#define _XOPEN_SOURCE 600 /* for usleep */
+#include <unistd.h>
+#include <stdint.h>
+
+#include <libavcodec/avcodec.h>
+#include <libavformat/avformat.h>
+#include <libavutil/opt.h>
+#include <assert.h>
+#include <ctype.h>
+
+#define MAX_METADATA_STREAMS 10
+
+static AVFormatContext *fmt_ctx;
+static AVCodecContext *dec_ctx[MAX_METADATA_STREAMS];
+static int metadata_stream_indices[MAX_METADATA_STREAMS + 1] = { -1 }; /* terminated with -1 */
+
+static int open_input_file(const char *filename)
+{
+    int ret;
+    AVCodec *dec = avcodec_find_decoder(AV_CODEC_ID_META);
+    int i;
+    int nb_metadata = 0;
+
+    if ((ret = avformat_open_input(&fmt_ctx, filename, NULL, NULL)) < 0) {
+        av_log(NULL, AV_LOG_ERROR, "Cannot open input file\n");
+        return ret;
+    }
+
+    if ((ret = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
+        av_log(NULL, AV_LOG_ERROR, "Cannot find stream information\n");
+        return ret;
+    }
+
+    for (i = 0; i < fmt_ctx->nb_streams; i++) {
+        if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_DATA) {
+            assert(nb_metadata < MAX_METADATA_STREAMS);
+            metadata_stream_indices[nb_metadata] = i;
+            nb_metadata++;
+        }
+    }
+    metadata_stream_indices[nb_metadata] = -1;
+
+    if (nb_metadata == 0) {
+        av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");
+        return ret;
+    }
+
+    for (i = 0; i < nb_metadata; i++) {
+        dec_ctx[i] = avcodec_alloc_context3(dec);
+        if ((ret = avcodec_open2(dec_ctx[i], dec, NULL)) < 0) {
+            av_log(NULL, AV_LOG_ERROR, "Cannot open metadata decoder for metadata stream on track %d\n", i);
+            return ret;
+        }
+    }
+
+    return 0;
+}
+
+static void* memndup(void* ptr, int n)
+{
+    void* buffer = malloc(n);
+    memcpy(buffer, ptr, n);
+    return buffer;
+}
+
+static char* local_strndup(char* str, int n)
+{
+    int len = 0;
+    while (str[len] && len < n) {
+        ++len;
+    }
+    char* buffer = malloc(n + 1);
+    memcpy(buffer, str, n);
+    buffer[len] = 0;
+    return buffer;
+}
+
+int main(int argc, char **argv)
+{
+    int ret;
+    AVPacket packet;
+    AVFrame *metadata = av_frame_alloc();
+    int i;
+
+    if (!metadata) {
+        perror("Could not allocate metadata");
+        exit(1);
+    }
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s file\n", argv[0]);
+        exit(1);
+    }
+
+    av_register_all();
+
+    if ((ret = open_input_file(argv[1])) < 0)
+        goto end;
+
+    for (i = 0; metadata_stream_indices[i] >= 0; i++) {
+        char *uri = NULL;
+        char *tref_tag = NULL;
+        int size;
+        int trefsSize;
+        AVTimedMetadataInfo* metadata =
+            (AVTimedMetadataInfo*) av_stream_get_side_data(fmt_ctx->streams[metadata_stream_indices[i]],
+                                                           AV_PKT_DATA_TIMED_METADATA_INFO,
+                                                           &size);
+        AVTrackReferences* trefs =
+            (AVTrackReferences*) av_stream_get_side_data(fmt_ctx->streams[metadata_stream_indices[i]],
+                                                         AV_PKT_DATA_TRACK_REFERENCES,
+                                                         &trefsSize);
+        if (!trefs)
+            printf("No track references!\n");
+        else if (!metadata)
+            printf("No metadata info!\n");
+        else if (metadata) {
+            tref_tag = local_strndup(metadata->meta_tag, 4);
+            uri = local_strndup((char*) (metadata + 1), metadata->meta_length);
+            int j;
+            int conf_len = metadata->conf_length;
+            void* conf = memndup((char*) (metadata + 1) + metadata->meta_length, metadata->conf_length);
+            char* conf_tag = local_strndup(metadata->conf_tag, 4);
+            printf("Track #%d describing track%s ",
+                   metadata_stream_indices[i] + 1,
+                   trefs->nb_tracks > 1 ? "s" : "");
+            for (j = 0; j < trefs->nb_tracks; ++j)
+                printf("#%d ", trefs->tracks[j]);
+            printf("with tref %s",
+                   tref_tag);
+            printf(" url: %s \n", uri);
+            printf(" configuration conf tag %s, %d bytes:", conf_tag, conf_len);
+            for (j = 0; j < conf_len; ++j) {
+                unsigned char ch = ((unsigned char*) conf)[j];
+                if (isprint(ch)) {
+                    printf(" %c", ch);
+                } else {
+                    printf(" %2x", ((unsigned char*) conf)[j]);
+                }
+            }
+            printf("\n");
+            free(conf);
+            free(conf_tag);
+            free(uri);
+            free(tref_tag);
+        } else {
+            printf("No meta data info for track  %d?!\n", metadata_stream_indices[i]);
+        }
+    }
+
+    /* read all packets */
+    while (1) {
+        if ((ret = av_read_frame(fmt_ctx, &packet)) < 0)
+            break;
+
+        for (i = 0; metadata_stream_indices[i] >= 0; i++) {
+            if (packet.stream_index == metadata_stream_indices[i]) {
+                ret = avcodec_send_packet(dec_ctx[i], &packet);
+
+                // We always empty decoded frames so we don't handle AVERROR(EAGAIN) here
+                if (ret < 0) {
+                    av_log(NULL, AV_LOG_ERROR, "Error decoding meta data\n");
+                    break;
+                }
+
+                while (avcodec_receive_frame(dec_ctx[i], metadata) == 0) {
+                    int c;
+                    printf("track #%d at %" PRId64 " (%d bytes), ",
+                           packet.stream_index + 1,
+                           metadata->pts,
+                           metadata->buf[0]->size);
+                    for (c = 0; c < metadata->buf[0]->size; ++c) {
+                        char ch = ((char*) metadata->buf[0]->data)[c];
+                        if (ch == '\\') {
+                            printf("\\\\");
+                        } else if (isprint(ch)) {
+                            putchar(ch);
+                        } else {
+                            printf("\\0x%2x", (unsigned char) ch);
+                        }
+                    }
+                    putchar('\n');
+                }
+            }
+        }
+        av_packet_unref(&packet);
+    }
+end:
+    for (i = 0; metadata_stream_indices[i] >= 0; i++) {
+        avcodec_close(dec_ctx[i]);
+    }
+    avformat_close_input(&fmt_ctx);
+    av_frame_free(&metadata);
+
+    if (ret < 0 && ret != AVERROR_EOF) {
+        fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
+        exit(1);
+    }
+
+    exit(0);
+}