ref: 8b2ddbc72845262f415e0d19d1f0e74388901722
dir: /examples/simple_encoder.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. */ // Simple Encoder // ============== // // This is an example of a simple encoder loop. It takes an input file in // YV12 format, passes it through the encoder, and writes the compressed // frames to disk in IVF format. Other decoder examples build upon this // one. // // The details of the IVF format have been elided from this example for // simplicity of presentation, as IVF files will not generally be used by // your application. In general, an IVF file consists of a file header, // followed by a variable number of frames. Each frame consists of a frame // header followed by a variable length payload. The length of the payload // is specified in the first four bytes of the frame header. The payload is // the raw compressed data. // // Standard Includes // ----------------- // For encoders, you only have to include `vpx_encoder.h` and then any // header files for the specific codecs you use. In this case, we're using // vp8. // // Getting The Default Configuration // --------------------------------- // Encoders have the notion of "usage profiles." For example, an encoder // may want to publish default configurations for both a video // conferencing application and a best quality offline encoder. These // obviously have very different default settings. Consult the // documentation for your codec to see if it provides any default // configurations. All codecs provide a default configuration, number 0, // which is valid for material in the vacinity of QCIF/QVGA. // // Updating The Configuration // --------------------------------- // Almost all applications will want to update the default configuration // with settings specific to their usage. Here we set the width and height // of the video file to that specified on the command line. We also scale // the default bitrate based on the ratio between the default resolution // and the resolution specified on the command line. // // Initializing The Codec // ---------------------- // The encoder is initialized by the following code. // // Encoding A Frame // ---------------- // The frame is read as a continuous block (size width * height * 3 / 2) // from the input file. If a frame was read (the input file has not hit // EOF) then the frame is passed to the encoder. Otherwise, a NULL // is passed, indicating the End-Of-Stream condition to the encoder. The // `frame_cnt` is reused as the presentation time stamp (PTS) and each // frame is shown for one frame-time in duration. The flags parameter is // unused in this example. The deadline is set to VPX_DL_REALTIME to // make the example run as quickly as possible. // Forced Keyframes // ---------------- // Keyframes can be forced by setting the VPX_EFLAG_FORCE_KF bit of the // flags passed to `vpx_codec_control()`. In this example, we force a // keyframe every <keyframe-interval> frames. Note, the output stream can // contain additional keyframes beyond those that have been forced using the // VPX_EFLAG_FORCE_KF flag because of automatic keyframe placement by the // encoder. // // Processing The Encoded Data // --------------------------- // Each packet of type `VPX_CODEC_CX_FRAME_PKT` contains the encoded data // for this frame. We write a IVF frame header, followed by the raw data. // // Cleanup // ------- // The `vpx_codec_destroy` call frees any memory allocated by the codec. // // Error Handling // -------------- // This example does not special case any error return codes. If there was // an error, a descriptive message is printed and the program exits. With // few exeptions, vpx_codec functions return an enumerated error status, // with the value `0` indicating success. // // Error Resiliency Features // ------------------------- // Error resiliency is controlled by the g_error_resilient member of the // configuration structure. Use the `decode_with_drops` example to decode with // frames 5-10 dropped. Compare the output for a file encoded with this example // versus one encoded with the `simple_encoder` example. #include <stdio.h> #include <stdlib.h> #include <string.h> #include "vpx/vpx_encoder.h" #include "../tools_common.h" #include "../video_writer.h" static const char *exec_name; void usage_exit(void) { fprintf(stderr, "Usage: %s <codec> <width> <height> <infile> <outfile> " "<keyframe-interval> [<error-resilient>]\nSee comments in " "simple_encoder.c for more information.\n", exec_name); exit(EXIT_FAILURE); } static int encode_frame(vpx_codec_ctx_t *codec, vpx_image_t *img, int frame_index, int flags, VpxVideoWriter *writer) { int got_pkts = 0; vpx_codec_iter_t iter = NULL; const vpx_codec_cx_pkt_t *pkt = NULL; const vpx_codec_err_t res = vpx_codec_encode(codec, img, frame_index, 1, flags, VPX_DL_GOOD_QUALITY); if (res != VPX_CODEC_OK) die_codec(codec, "Failed to encode frame"); while ((pkt = vpx_codec_get_cx_data(codec, &iter)) != NULL) { got_pkts = 1; if (pkt->kind == VPX_CODEC_CX_FRAME_PKT) { const int keyframe = (pkt->data.frame.flags & VPX_FRAME_IS_KEY) != 0; if (!vpx_video_writer_write_frame(writer, pkt->data.frame.buf, pkt->data.frame.sz, pkt->data.frame.pts)) { die_codec(codec, "Failed to write compressed frame"); } printf(keyframe ? "K" : "."); fflush(stdout); } } return got_pkts; } int main(int argc, char **argv) { FILE *infile = NULL; vpx_codec_ctx_t codec; vpx_codec_enc_cfg_t cfg; int frame_count = 0; vpx_image_t raw; vpx_codec_err_t res; VpxVideoInfo info = {0}; VpxVideoWriter *writer = NULL; const VpxInterface *encoder = NULL; const int fps = 30; // TODO(dkovalev) add command line argument const int bitrate = 200; // kbit/s TODO(dkovalev) add command line argument int keyframe_interval = 0; // TODO(dkovalev): Add some simple command line parsing code to make the // command line more flexible. const char *codec_arg = NULL; const char *width_arg = NULL; const char *height_arg = NULL; const char *infile_arg = NULL; const char *outfile_arg = NULL; const char *keyframe_interval_arg = NULL; exec_name = argv[0]; if (argc < 7) die("Invalid number of arguments"); codec_arg = argv[1]; width_arg = argv[2]; height_arg = argv[3]; infile_arg = argv[4]; outfile_arg = argv[5]; keyframe_interval_arg = argv[6]; encoder = get_vpx_encoder_by_name(codec_arg); if (!encoder) die("Unsupported codec."); info.codec_fourcc = encoder->fourcc; info.frame_width = strtol(width_arg, NULL, 0); info.frame_height = strtol(height_arg, NULL, 0); info.time_base.numerator = 1; info.time_base.denominator = fps; if (info.frame_width <= 0 || info.frame_height <= 0 || (info.frame_width % 2) != 0 || (info.frame_height % 2) != 0) { die("Invalid frame size: %dx%d", info.frame_width, info.frame_height); } if (!vpx_img_alloc(&raw, VPX_IMG_FMT_I420, info.frame_width, info.frame_height, 1)) { die("Failed to allocate image."); } keyframe_interval = strtol(keyframe_interval_arg, NULL, 0); if (keyframe_interval < 0) die("Invalid keyframe interval value."); printf("Using %s\n", vpx_codec_iface_name(encoder->codec_interface())); res = vpx_codec_enc_config_default(encoder->codec_interface(), &cfg, 0); if (res) die_codec(&codec, "Failed to get default codec config."); cfg.g_w = info.frame_width; cfg.g_h = info.frame_height; cfg.g_timebase.num = info.time_base.numerator; cfg.g_timebase.den = info.time_base.denominator; cfg.rc_target_bitrate = bitrate; cfg.g_error_resilient = argc > 7 ? strtol(argv[7], NULL, 0) : 0; writer = vpx_video_writer_open(outfile_arg, kContainerIVF, &info); if (!writer) die("Failed to open %s for writing.", outfile_arg); if (!(infile = fopen(infile_arg, "rb"))) die("Failed to open %s for reading.", infile_arg); if (vpx_codec_enc_init(&codec, encoder->codec_interface(), &cfg, 0)) die_codec(&codec, "Failed to initialize encoder"); // Encode frames. while (vpx_img_read(&raw, infile)) { int flags = 0; if (keyframe_interval > 0 && frame_count % keyframe_interval == 0) flags |= VPX_EFLAG_FORCE_KF; encode_frame(&codec, &raw, frame_count++, flags, writer); } // Flush encoder. while (encode_frame(&codec, NULL, -1, 0, writer)) {}; printf("\n"); fclose(infile); printf("Processed %d frames.\n", frame_count); vpx_img_free(&raw); if (vpx_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec."); vpx_video_writer_close(writer); return EXIT_SUCCESS; }