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Diffstat (limited to 'doc/examples/avcodec.c')
-rw-r--r-- | doc/examples/avcodec.c | 421 |
1 files changed, 0 insertions, 421 deletions
diff --git a/doc/examples/avcodec.c b/doc/examples/avcodec.c deleted file mode 100644 index 63812d99c3..0000000000 --- a/doc/examples/avcodec.c +++ /dev/null @@ -1,421 +0,0 @@ -/* - * copyright (c) 2001 Fabrice Bellard - * - * This file is part of Libav. - * - * Libav is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * Libav is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with Libav; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -/** - * @file - * libavcodec API use example. - * - * @example avcodec.c - * Note that this library only handles codecs (MPEG, MPEG-4, etc...), - * not file formats (AVI, VOB, etc...). See library 'libavformat' for the - * format handling. - */ - -#include <stdlib.h> -#include <stdio.h> -#include <string.h> - -#ifdef HAVE_AV_CONFIG_H -#undef HAVE_AV_CONFIG_H -#endif - -#include "libavcodec/avcodec.h" -#include "libavutil/channel_layout.h" -#include "libavutil/common.h" -#include "libavutil/imgutils.h" -#include "libavutil/mathematics.h" -#include "libavutil/samplefmt.h" - -#define INBUF_SIZE 4096 -#define AUDIO_INBUF_SIZE 20480 -#define AUDIO_REFILL_THRESH 4096 - -/* - * Audio decoding. - */ -static void audio_decode_example(const char *outfilename, const char *filename) -{ - AVCodec *codec; - AVCodecContext *c= NULL; - int len; - FILE *f, *outfile; - uint8_t inbuf[AUDIO_INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; - AVPacket avpkt; - AVFrame *decoded_frame = NULL; - - av_init_packet(&avpkt); - - printf("Audio decoding\n"); - - /* find the MPEG audio decoder */ - codec = avcodec_find_decoder(AV_CODEC_ID_MP2); - if (!codec) { - fprintf(stderr, "codec not found\n"); - exit(1); - } - - c = avcodec_alloc_context3(codec); - - /* open it */ - if (avcodec_open2(c, codec, NULL) < 0) { - fprintf(stderr, "could not open codec\n"); - exit(1); - } - - f = fopen(filename, "rb"); - if (!f) { - fprintf(stderr, "could not open %s\n", filename); - exit(1); - } - outfile = fopen(outfilename, "wb"); - if (!outfile) { - av_free(c); - exit(1); - } - - /* decode until eof */ - avpkt.data = inbuf; - avpkt.size = fread(inbuf, 1, AUDIO_INBUF_SIZE, f); - - while (avpkt.size > 0) { - int got_frame = 0; - - if (!decoded_frame) { - if (!(decoded_frame = av_frame_alloc())) { - fprintf(stderr, "out of memory\n"); - exit(1); - } - } - - len = avcodec_decode_audio4(c, decoded_frame, &got_frame, &avpkt); - if (len < 0) { - fprintf(stderr, "Error while decoding\n"); - exit(1); - } - if (got_frame) { - /* if a frame has been decoded, output it */ - int data_size = av_samples_get_buffer_size(NULL, c->channels, - decoded_frame->nb_samples, - c->sample_fmt, 1); - fwrite(decoded_frame->data[0], 1, data_size, outfile); - } - avpkt.size -= len; - avpkt.data += len; - if (avpkt.size < AUDIO_REFILL_THRESH) { - /* Refill the input buffer, to avoid trying to decode - * incomplete frames. Instead of this, one could also use - * a parser, or use a proper container format through - * libavformat. */ - memmove(inbuf, avpkt.data, avpkt.size); - avpkt.data = inbuf; - len = fread(avpkt.data + avpkt.size, 1, - AUDIO_INBUF_SIZE - avpkt.size, f); - if (len > 0) - avpkt.size += len; - } - } - - fclose(outfile); - fclose(f); - - avcodec_free_context(&c); - av_frame_free(&decoded_frame); -} - -/* - * Video encoding example - */ -static void video_encode_example(const char *filename) -{ - AVCodec *codec; - AVCodecContext *c= NULL; - int i, ret, x, y, got_output; - FILE *f; - AVFrame *picture; - AVPacket pkt; - uint8_t endcode[] = { 0, 0, 1, 0xb7 }; - - printf("Video encoding\n"); - - /* find the mpeg1video encoder */ - codec = avcodec_find_encoder(AV_CODEC_ID_MPEG1VIDEO); - if (!codec) { - fprintf(stderr, "codec not found\n"); - exit(1); - } - - c = avcodec_alloc_context3(codec); - picture = av_frame_alloc(); - - /* put sample parameters */ - c->bit_rate = 400000; - /* resolution must be a multiple of two */ - c->width = 352; - c->height = 288; - /* frames per second */ - c->time_base= (AVRational){1,25}; - c->gop_size = 10; /* emit one intra frame every ten frames */ - c->max_b_frames=1; - c->pix_fmt = AV_PIX_FMT_YUV420P; - - /* open it */ - if (avcodec_open2(c, codec, NULL) < 0) { - fprintf(stderr, "could not open codec\n"); - exit(1); - } - - f = fopen(filename, "wb"); - if (!f) { - fprintf(stderr, "could not open %s\n", filename); - exit(1); - } - - ret = av_image_alloc(picture->data, picture->linesize, c->width, c->height, - c->pix_fmt, 32); - if (ret < 0) { - fprintf(stderr, "could not alloc raw picture buffer\n"); - exit(1); - } - picture->format = c->pix_fmt; - picture->width = c->width; - picture->height = c->height; - - /* encode 1 second of video */ - for(i=0;i<25;i++) { - av_init_packet(&pkt); - pkt.data = NULL; // packet data will be allocated by the encoder - pkt.size = 0; - - fflush(stdout); - /* prepare a dummy image */ - /* Y */ - for(y=0;y<c->height;y++) { - for(x=0;x<c->width;x++) { - picture->data[0][y * picture->linesize[0] + x] = x + y + i * 3; - } - } - - /* Cb and Cr */ - for(y=0;y<c->height/2;y++) { - for(x=0;x<c->width/2;x++) { - picture->data[1][y * picture->linesize[1] + x] = 128 + y + i * 2; - picture->data[2][y * picture->linesize[2] + x] = 64 + x + i * 5; - } - } - - picture->pts = i; - - /* encode the image */ - ret = avcodec_encode_video2(c, &pkt, picture, &got_output); - if (ret < 0) { - fprintf(stderr, "error encoding frame\n"); - exit(1); - } - - if (got_output) { - printf("encoding frame %3d (size=%5d)\n", i, pkt.size); - fwrite(pkt.data, 1, pkt.size, f); - av_packet_unref(&pkt); - } - } - - /* get the delayed frames */ - for (got_output = 1; got_output; i++) { - fflush(stdout); - - ret = avcodec_encode_video2(c, &pkt, NULL, &got_output); - if (ret < 0) { - fprintf(stderr, "error encoding frame\n"); - exit(1); - } - - if (got_output) { - printf("encoding frame %3d (size=%5d)\n", i, pkt.size); - fwrite(pkt.data, 1, pkt.size, f); - av_packet_unref(&pkt); - } - } - - /* add sequence end code to have a real MPEG file */ - fwrite(endcode, 1, sizeof(endcode), f); - fclose(f); - - avcodec_free_context(&c); - av_freep(&picture->data[0]); - av_frame_free(&picture); - printf("\n"); -} - -/* - * Video decoding example - */ - -static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize, - char *filename) -{ - FILE *f; - int i; - - f=fopen(filename,"w"); - fprintf(f,"P5\n%d %d\n%d\n",xsize,ysize,255); - for(i=0;i<ysize;i++) - fwrite(buf + i * wrap,1,xsize,f); - fclose(f); -} - -static void video_decode_example(const char *outfilename, const char *filename) -{ - AVCodec *codec; - AVCodecContext *c= NULL; - int frame, got_picture, len; - FILE *f; - AVFrame *picture; - uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; - char buf[1024]; - AVPacket avpkt; - - av_init_packet(&avpkt); - - /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */ - memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE); - - printf("Video decoding\n"); - - /* find the MPEG-1 video decoder */ - codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO); - if (!codec) { - fprintf(stderr, "codec not found\n"); - exit(1); - } - - c = avcodec_alloc_context3(codec); - picture = av_frame_alloc(); - - if (codec->capabilities & AV_CODEC_CAP_TRUNCATED) - c->flags |= AV_CODEC_FLAG_TRUNCATED; // we do not send complete frames - - /* For some codecs, such as msmpeg4 and mpeg4, width and height - MUST be initialized there because this information is not - available in the bitstream. */ - - /* open it */ - if (avcodec_open2(c, codec, NULL) < 0) { - fprintf(stderr, "could not open codec\n"); - exit(1); - } - - /* the codec gives us the frame size, in samples */ - - f = fopen(filename, "rb"); - if (!f) { - fprintf(stderr, "could not open %s\n", filename); - exit(1); - } - - frame = 0; - for(;;) { - avpkt.size = fread(inbuf, 1, INBUF_SIZE, f); - if (avpkt.size == 0) - break; - - /* NOTE1: some codecs are stream based (mpegvideo, mpegaudio) - and this is the only method to use them because you cannot - know the compressed data size before analysing it. - - BUT some other codecs (msmpeg4, mpeg4) are inherently frame - based, so you must call them with all the data for one - frame exactly. You must also initialize 'width' and - 'height' before initializing them. */ - - /* NOTE2: some codecs allow the raw parameters (frame size, - sample rate) to be changed at any frame. We handle this, so - you should also take care of it */ - - /* here, we use a stream based decoder (mpeg1video), so we - feed decoder and see if it could decode a frame */ - avpkt.data = inbuf; - while (avpkt.size > 0) { - len = avcodec_decode_video2(c, picture, &got_picture, &avpkt); - if (len < 0) { - fprintf(stderr, "Error while decoding frame %d\n", frame); - exit(1); - } - if (got_picture) { - printf("saving frame %3d\n", frame); - fflush(stdout); - - /* the picture is allocated by the decoder. no need to - free it */ - snprintf(buf, sizeof(buf), outfilename, frame); - pgm_save(picture->data[0], picture->linesize[0], - c->width, c->height, buf); - frame++; - } - avpkt.size -= len; - avpkt.data += len; - } - } - - /* Some codecs, such as MPEG, transmit the I- and P-frame with a - latency of one frame. You must do the following to have a - chance to get the last frame of the video. */ - avpkt.data = NULL; - avpkt.size = 0; - len = avcodec_decode_video2(c, picture, &got_picture, &avpkt); - if (got_picture) { - printf("saving last frame %3d\n", frame); - fflush(stdout); - - /* the picture is allocated by the decoder. no need to - free it */ - snprintf(buf, sizeof(buf), outfilename, frame); - pgm_save(picture->data[0], picture->linesize[0], - c->width, c->height, buf); - frame++; - } - - fclose(f); - - avcodec_free_context(&c); - av_frame_free(&picture); - printf("\n"); -} - -int main(int argc, char **argv) -{ - const char *filename; - - /* register all the codecs */ - avcodec_register_all(); - - if (argc <= 1) { - audio_decode_example("/tmp/test.sw", "/tmp/test.mp2"); - - video_encode_example("/tmp/test.mpg"); - filename = "/tmp/test.mpg"; - } else { - filename = argv[1]; - } - - // audio_decode_example("/tmp/test.sw", filename); - video_decode_example("/tmp/test%d.pgm", filename); - - return 0; -} |