tor-browser

simple_encoder.c (9512B)

---

/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved.
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/

// 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 `aom_encoder.h` and then any
// header files for the specific codecs you use. In this case, we're using
// aom.
//
// 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.

// Forced Keyframes
// ----------------
// Keyframes can be forced by setting the AOM_EFLAG_FORCE_KF bit of the
// flags passed to `aom_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
// AOM_EFLAG_FORCE_KF flag because of automatic keyframe placement by the
// encoder.
//
// Processing The Encoded Data
// ---------------------------
// Each packet of type `AOM_CODEC_CX_FRAME_PKT` contains the encoded data
// for this frame. We write a IVF frame header, followed by the raw data.
//
// Cleanup
// -------
// The `aom_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, aom_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 "aom/aom_encoder.h"
#include "aom/aomcx.h"
#include "common/tools_common.h"
#include "common/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> <frames to encode>\n"
         "See comments in simple_encoder.c for more information.\n",
         exec_name);
 exit(EXIT_FAILURE);
}

static int encode_frame(aom_codec_ctx_t *codec, aom_image_t *img,
                       int frame_index, int flags, AvxVideoWriter *writer) {
 int got_pkts = 0;
 aom_codec_iter_t iter = NULL;
 const aom_codec_cx_pkt_t *pkt = NULL;
 const aom_codec_err_t res =
     aom_codec_encode(codec, img, frame_index, 1, flags);
 if (res != AOM_CODEC_OK) die_codec(codec, "Failed to encode frame");

 while ((pkt = aom_codec_get_cx_data(codec, &iter)) != NULL) {
   got_pkts = 1;

   if (pkt->kind == AOM_CODEC_CX_FRAME_PKT) {
     const int keyframe = (pkt->data.frame.flags & AOM_FRAME_IS_KEY) != 0;
     if (!aom_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;
}

// TODO(tomfinegan): Improve command line parsing and add args for bitrate/fps.
int main(int argc, char **argv) {
 FILE *infile = NULL;
 aom_codec_ctx_t codec;
 aom_codec_enc_cfg_t cfg;
 int frame_count = 0;
 aom_image_t raw;
 aom_codec_err_t res;
 AvxVideoInfo info;
 AvxVideoWriter *writer = NULL;
 const int fps = 30;
 const int bitrate = 200;
 int keyframe_interval = 0;
 int max_frames = 0;
 int frames_encoded = 0;
 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;
#if CONFIG_REALTIME_ONLY
 const int usage = 1;
 const int speed = 7;
#else
 const int usage = 0;
 const int speed = 2;
#endif

 exec_name = argv[0];

 // Clear explicitly, as simply assigning "{ 0 }" generates
 // "missing-field-initializers" warning in some compilers.
 memset(&info, 0, sizeof(info));

 if (argc != 9) 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];
 max_frames = (int)strtol(argv[8], NULL, 0);

 aom_codec_iface_t *encoder = get_aom_encoder_by_short_name(codec_arg);
 if (!encoder) die("Unsupported codec.");

 info.codec_fourcc = get_fourcc_by_aom_encoder(encoder);
 info.frame_width = (int)strtol(width_arg, NULL, 0);
 info.frame_height = (int)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 (!aom_img_alloc(&raw, AOM_IMG_FMT_I420, info.frame_width,
                    info.frame_height, 1)) {
   die("Failed to allocate image.");
 }

 keyframe_interval = (int)strtol(keyframe_interval_arg, NULL, 0);
 if (keyframe_interval < 0) die("Invalid keyframe interval value.");

 printf("Using %s\n", aom_codec_iface_name(encoder));

 res = aom_codec_enc_config_default(encoder, &cfg, usage);
 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 = (aom_codec_er_flags_t)strtoul(argv[7], NULL, 0);

 writer = aom_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 (aom_codec_enc_init(&codec, encoder, &cfg, 0))
   die("Failed to initialize encoder");

 if (aom_codec_control(&codec, AOME_SET_CPUUSED, speed))
   die_codec(&codec, "Failed to set cpu-used");

 // Encode frames.
 while (aom_img_read(&raw, infile)) {
   int flags = 0;
   if (keyframe_interval > 0 && frame_count % keyframe_interval == 0)
     flags |= AOM_EFLAG_FORCE_KF;
   encode_frame(&codec, &raw, frame_count++, flags, writer);
   frames_encoded++;
   if (max_frames > 0 && frames_encoded >= max_frames) break;
 }

 // Flush encoder.
 while (encode_frame(&codec, NULL, -1, 0, writer)) continue;

 printf("\n");
 fclose(infile);
 printf("Processed %d frames.\n", frame_count);

 aom_img_free(&raw);
 if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec.");

 aom_video_writer_close(writer);

 return EXIT_SUCCESS;
}