ref: b8c2a4eb0c47b633096f5c428b70607e7bf8d570
dir: /examples/decode_with_drops.c/
/* * Copyright (c) 2010 The WebM project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ // Decode With Drops Example // ========================= // // This is an example utility which drops a series of frames, as specified // on the command line. This is useful for observing the error recovery // features of the codec. // // Usage // ----- // This example adds a single argument to the `simple_decoder` example, // which specifies the range or pattern of frames to drop. The parameter is // parsed as follows: // // Dropping A Range Of Frames // -------------------------- // To drop a range of frames, specify the starting frame and the ending // frame to drop, separated by a dash. The following command will drop // frames 5 through 10 (base 1). // // $ ./decode_with_drops in.ivf out.i420 5-10 // // // Dropping A Pattern Of Frames // ---------------------------- // To drop a pattern of frames, specify the number of frames to drop and // the number of frames after which to repeat the pattern, separated by // a forward-slash. The following command will drop 3 of 7 frames. // Specifically, it will decode 4 frames, then drop 3 frames, and then // repeat. // // $ ./decode_with_drops in.ivf out.i420 3/7 // // // Extra Variables // --------------- // This example maintains the pattern passed on the command line in the // `n`, `m`, and `is_range` variables: // // // Making The Drop Decision // ------------------------ // The example decides whether to drop the frame based on the current // frame number, immediately before decoding the frame. #include <stdio.h> #include <stdlib.h> #include <string.h> #include "vpx/vp8dx.h" #include "vpx/vpx_decoder.h" #include "../tools_common.h" #include "../video_reader.h" #include "./vpx_config.h" static const char *exec_name; void usage_exit(void) { fprintf(stderr, "Usage: %s <infile> <outfile> <N-M|N/M>\n", exec_name); exit(EXIT_FAILURE); } int main(int argc, char **argv) { int frame_cnt = 0; FILE *outfile = NULL; vpx_codec_ctx_t codec; const VpxInterface *decoder = NULL; VpxVideoReader *reader = NULL; const VpxVideoInfo *info = NULL; int n = 0; int m = 0; int is_range = 0; char *nptr = NULL; exec_name = argv[0]; if (argc != 4) die("Invalid number of arguments."); reader = vpx_video_reader_open(argv[1]); if (!reader) die("Failed to open %s for reading.", argv[1]); if (!(outfile = fopen(argv[2], "wb"))) die("Failed to open %s for writing.", argv[2]); n = strtol(argv[3], &nptr, 0); m = strtol(nptr + 1, NULL, 0); is_range = (*nptr == '-'); if (!n || !m || (*nptr != '-' && *nptr != '/')) die("Couldn't parse pattern %s.\n", argv[3]); info = vpx_video_reader_get_info(reader); decoder = get_vpx_decoder_by_fourcc(info->codec_fourcc); if (!decoder) die("Unknown input codec."); printf("Using %s\n", vpx_codec_iface_name(decoder->codec_interface())); if (vpx_codec_dec_init(&codec, decoder->codec_interface(), NULL, 0)) die_codec(&codec, "Failed to initialize decoder."); while (vpx_video_reader_read_frame(reader)) { vpx_codec_iter_t iter = NULL; vpx_image_t *img = NULL; size_t frame_size = 0; int skip; const unsigned char *frame = vpx_video_reader_get_frame(reader, &frame_size); if (vpx_codec_decode(&codec, frame, (unsigned int)frame_size, NULL, 0)) die_codec(&codec, "Failed to decode frame."); ++frame_cnt; skip = (is_range && frame_cnt >= n && frame_cnt <= m) || (!is_range && m - (frame_cnt - 1) % m <= n); if (!skip) { putc('.', stdout); while ((img = vpx_codec_get_frame(&codec, &iter)) != NULL) vpx_img_write(img, outfile); } else { putc('X', stdout); } fflush(stdout); } printf("Processed %d frames.\n", frame_cnt); if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec."); printf("Play: ffplay -f rawvideo -pix_fmt yuv420p -s %dx%d %s\n", info->frame_width, info->frame_height, argv[2]); vpx_video_reader_close(reader); fclose(outfile); return EXIT_SUCCESS; }