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-rw-r--r--doc/examples/extract_mvs.c185
1 files changed, 185 insertions, 0 deletions
diff --git a/doc/examples/extract_mvs.c b/doc/examples/extract_mvs.c
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+++ b/doc/examples/extract_mvs.c
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+/*
+ * Copyright (c) 2012 Stefano Sabatini
+ * Copyright (c) 2014 Clément Bœsch
+ *
+ * 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.
+ */
+
+#include <libavutil/motion_vector.h>
+#include <libavformat/avformat.h>
+
+static AVFormatContext *fmt_ctx = NULL;
+static AVCodecContext *video_dec_ctx = NULL;
+static AVStream *video_stream = NULL;
+static const char *src_filename = NULL;
+
+static int video_stream_idx = -1;
+static AVFrame *frame = NULL;
+static AVPacket pkt;
+static int video_frame_count = 0;
+
+static int decode_packet(int *got_frame, int cached)
+{
+ int decoded = pkt.size;
+
+ *got_frame = 0;
+
+ if (pkt.stream_index == video_stream_idx) {
+ int ret = avcodec_decode_video2(video_dec_ctx, frame, got_frame, &pkt);
+ if (ret < 0) {
+ fprintf(stderr, "Error decoding video frame (%s)\n", av_err2str(ret));
+ return ret;
+ }
+
+ if (*got_frame) {
+ int i;
+ AVFrameSideData *sd;
+
+ video_frame_count++;
+ sd = av_frame_get_side_data(frame, AV_FRAME_DATA_MOTION_VECTORS);
+ if (sd) {
+ const AVMotionVector *mvs = (const AVMotionVector *)sd->data;
+ for (i = 0; i < sd->size / sizeof(*mvs); i++) {
+ const AVMotionVector *mv = &mvs[i];
+ printf("%d,%2d,%2d,%2d,%4d,%4d,%4d,%4d,0x%"PRIx64"\n",
+ video_frame_count, mv->source,
+ mv->w, mv->h, mv->src_x, mv->src_y,
+ mv->dst_x, mv->dst_y, mv->flags);
+ }
+ }
+ }
+ }
+
+ return decoded;
+}
+
+static int open_codec_context(int *stream_idx,
+ AVFormatContext *fmt_ctx, enum AVMediaType type)
+{
+ int ret;
+ AVStream *st;
+ AVCodecContext *dec_ctx = NULL;
+ AVCodec *dec = NULL;
+ AVDictionary *opts = NULL;
+
+ ret = av_find_best_stream(fmt_ctx, type, -1, -1, NULL, 0);
+ if (ret < 0) {
+ fprintf(stderr, "Could not find %s stream in input file '%s'\n",
+ av_get_media_type_string(type), src_filename);
+ return ret;
+ } else {
+ *stream_idx = ret;
+ st = fmt_ctx->streams[*stream_idx];
+
+ /* find decoder for the stream */
+ dec_ctx = st->codec;
+ dec = avcodec_find_decoder(dec_ctx->codec_id);
+ if (!dec) {
+ fprintf(stderr, "Failed to find %s codec\n",
+ av_get_media_type_string(type));
+ return AVERROR(EINVAL);
+ }
+
+ /* Init the video decoder */
+ av_dict_set(&opts, "flags2", "+export_mvs", 0);
+ if ((ret = avcodec_open2(dec_ctx, dec, &opts)) < 0) {
+ fprintf(stderr, "Failed to open %s codec\n",
+ av_get_media_type_string(type));
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int ret = 0, got_frame;
+
+ if (argc != 2) {
+ fprintf(stderr, "Usage: %s <video>\n", argv[0]);
+ exit(1);
+ }
+ src_filename = argv[1];
+
+ av_register_all();
+
+ if (avformat_open_input(&fmt_ctx, src_filename, NULL, NULL) < 0) {
+ fprintf(stderr, "Could not open source file %s\n", src_filename);
+ exit(1);
+ }
+
+ if (avformat_find_stream_info(fmt_ctx, NULL) < 0) {
+ fprintf(stderr, "Could not find stream information\n");
+ exit(1);
+ }
+
+ if (open_codec_context(&video_stream_idx, fmt_ctx, AVMEDIA_TYPE_VIDEO) >= 0) {
+ video_stream = fmt_ctx->streams[video_stream_idx];
+ video_dec_ctx = video_stream->codec;
+ }
+
+ av_dump_format(fmt_ctx, 0, src_filename, 0);
+
+ if (!video_stream) {
+ fprintf(stderr, "Could not find video stream in the input, aborting\n");
+ ret = 1;
+ goto end;
+ }
+
+ frame = av_frame_alloc();
+ if (!frame) {
+ fprintf(stderr, "Could not allocate frame\n");
+ ret = AVERROR(ENOMEM);
+ goto end;
+ }
+
+ printf("framenum,source,blockw,blockh,srcx,srcy,dstx,dsty,flags\n");
+
+ /* initialize packet, set data to NULL, let the demuxer fill it */
+ av_init_packet(&pkt);
+ pkt.data = NULL;
+ pkt.size = 0;
+
+ /* read frames from the file */
+ while (av_read_frame(fmt_ctx, &pkt) >= 0) {
+ AVPacket orig_pkt = pkt;
+ do {
+ ret = decode_packet(&got_frame, 0);
+ if (ret < 0)
+ break;
+ pkt.data += ret;
+ pkt.size -= ret;
+ } while (pkt.size > 0);
+ av_free_packet(&orig_pkt);
+ }
+
+ /* flush cached frames */
+ pkt.data = NULL;
+ pkt.size = 0;
+ do {
+ decode_packet(&got_frame, 1);
+ } while (got_frame);
+
+end:
+ avcodec_close(video_dec_ctx);
+ avformat_close_input(&fmt_ctx);
+ av_frame_free(&frame);
+ return ret < 0;
+}