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-rw-r--r-- | third_party/aom/examples/simple_decoder.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/third_party/aom/examples/simple_decoder.c b/third_party/aom/examples/simple_decoder.c new file mode 100644 index 0000000000..b6891dcbba --- /dev/null +++ b/third_party/aom/examples/simple_decoder.c @@ -0,0 +1,145 @@ +/* + * 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 Decoder +// ============== +// +// This is an example of a simple decoder loop. It takes an input file +// containing the compressed data (in IVF format), passes it through the +// decoder, and writes the decompressed frames to disk. 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 decoders, you only have to include `aom_decoder.h` and then any +// header files for the specific codecs you use. In this case, we're using +// aom. +// +// Initializing The Codec +// ---------------------- +// The libaom decoder is initialized by the call to aom_codec_dec_init(). +// Determining the codec interface to use is handled by AvxVideoReader and the +// functions prefixed with aom_video_reader_. Discussion of those functions is +// beyond the scope of this example, but the main gist is to open the input file +// and parse just enough of it to determine if it's a AVx file and which AVx +// codec is contained within the file. +// Note the NULL pointer passed to aom_codec_dec_init(). We do that in this +// example because we want the algorithm to determine the stream configuration +// (width/height) and allocate memory automatically. +// +// Decoding A Frame +// ---------------- +// Once the frame has been read into memory, it is decoded using the +// `aom_codec_decode` function. The call takes a pointer to the data +// (`frame`) and the length of the data (`frame_size`). No application data +// is associated with the frame in this example, so the `user_priv` +// parameter is NULL. +// +// Codecs may produce a variable number of output frames for every call to +// `aom_codec_decode`. These frames are retrieved by the +// `aom_codec_get_frame` iterator function. The iterator variable `iter` is +// initialized to NULL each time `aom_codec_decode` is called. +// `aom_codec_get_frame` is called in a loop, returning a pointer to a +// decoded image or NULL to indicate the end of list. +// +// Processing The Decoded Data +// --------------------------- +// In this example, we simply write the encoded data to disk. It is +// important to honor the image's `stride` values. +// +// 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 exceptions, aom_codec functions return an enumerated error status, +// with the value `0` indicating success. + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "aom/aom_decoder.h" +#include "common/tools_common.h" +#include "common/video_reader.h" + +static const char *exec_name; + +void usage_exit(void) { + fprintf(stderr, "Usage: %s <infile> <outfile>\n", exec_name); + exit(EXIT_FAILURE); +} + +int main(int argc, char **argv) { + int frame_cnt = 0; + FILE *outfile = NULL; + AvxVideoReader *reader = NULL; + const AvxVideoInfo *info = NULL; + + exec_name = argv[0]; + + if (argc != 3) die("Invalid number of arguments."); + + reader = aom_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]); + + info = aom_video_reader_get_info(reader); + + aom_codec_iface_t *decoder = get_aom_decoder_by_fourcc(info->codec_fourcc); + if (!decoder) die("Unknown input codec."); + + printf("Using %s\n", aom_codec_iface_name(decoder)); + + aom_codec_ctx_t codec; + if (aom_codec_dec_init(&codec, decoder, NULL, 0)) + die("Failed to initialize decoder."); + + while (aom_video_reader_read_frame(reader)) { + aom_codec_iter_t iter = NULL; + aom_image_t *img = NULL; + size_t frame_size = 0; + const unsigned char *frame = + aom_video_reader_get_frame(reader, &frame_size); + if (aom_codec_decode(&codec, frame, frame_size, NULL)) + die_codec(&codec, "Failed to decode frame."); + + while ((img = aom_codec_get_frame(&codec, &iter)) != NULL) { + aom_img_write(img, outfile); + ++frame_cnt; + } + } + + printf("Processed %d frames.\n", frame_cnt); + if (aom_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]); + + aom_video_reader_close(reader); + + fclose(outfile); + + return EXIT_SUCCESS; +} |