/* * 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 libavcodec/api-example.c * Note that this library only handles codecs (mpeg, mpeg4, 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 /* check that a given sample format is supported by the encoder */static int check_sample_fmt(AVCodec *codec, enum AVSampleFormat sample_fmt){    const enum AVSampleFormat *p = codec->sample_fmts;     while (*p != AV_SAMPLE_FMT_NONE) {        if (*p == sample_fmt)            return 1;        p++;    }    return 0;} /* just pick the highest supported samplerate */static int select_sample_rate(AVCodec *codec){    const int *p;    int best_samplerate = 0;     if (!codec->supported_samplerates)        return 44100;     p = codec->supported_samplerates;    while (*p) {        best_samplerate = FFMAX(*p, best_samplerate);        p++;    }    return best_samplerate;} /* select layout with the highest channel count */static int select_channel_layout(AVCodec *codec){    const uint64_t *p;    uint64_t best_ch_layout = 0;    int best_nb_channels   = 0;     if (!codec->channel_layouts)        return AV_CH_LAYOUT_STEREO;     p = codec->channel_layouts;    while (*p) {        int nb_channels = av_get_channel_layout_nb_channels(*p);         if (nb_channels > best_nb_channels) {            best_ch_layout    = *p;            best_nb_channels = nb_channels;        }        p++;    }    return best_ch_layout;} /* * Audio encoding example */static void audio_encode_example(const char *filename){    AVCodec *codec;    AVCodecContext *c= NULL;    AVFrame *frame;    AVPacket pkt;    int i, j, k, ret, got_output;    int buffer_size;    FILE *f;    uint16_t *samples;    float t, tincr;     printf("Audio encoding\n");     /* find the MP2 encoder */    codec = avcodec_find_encoder(AV_CODEC_ID_MP2);    if (!codec) {        fprintf(stderr, "codec not found\n");        exit(1);    }     c = avcodec_alloc_context3(codec);     /* put sample parameters */    c->bit_rate = 64000;     /* check that the encoder supports s16 pcm input */    c->sample_fmt = AV_SAMPLE_FMT_S16;    if (!check_sample_fmt(codec, c->sample_fmt)) {        fprintf(stderr, "encoder does not support %s",                av_get_sample_fmt_name(c->sample_fmt));        exit(1);    }     /* select other audio parameters supported by the encoder */    c->sample_rate    = select_sample_rate(codec);    c->channel_layout = select_channel_layout(codec);    c->channels       = av_get_channel_layout_nb_channels(c->channel_layout);     /* 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);    }     /* frame containing input raw audio */    frame = avcodec_alloc_frame();    if (!frame) {        fprintf(stderr, "could not allocate audio frame\n");        exit(1);    }     frame->nb_samples     = c->frame_size;    frame->format         = c->sample_fmt;    frame->channel_layout = c->channel_layout;     /* the codec gives us the frame size, in samples,     * we calculate the size of the samples buffer in bytes */    buffer_size = av_samples_get_buffer_size(NULL, c->channels, c->frame_size,                                             c->sample_fmt, 0);    samples = av_malloc(buffer_size);    if (!samples) {        fprintf(stderr, "could not allocate %d bytes for samples buffer\n",                buffer_size);        exit(1);    }    /* setup the data pointers in the AVFrame */    ret = avcodec_fill_audio_frame(frame, c->channels, c->sample_fmt,                                   (const uint8_t*)samples, buffer_size, 0);    if (ret < 0) {        fprintf(stderr, "could not setup audio frame\n");        exit(1);    }     /* encode a single tone sound */    t = 0;    tincr = 2 * M_PI * 440.0 / c->sample_rate;    for(i=0;i<200;i++) {        av_init_packet(&pkt);        pkt.data = NULL; // packet data will be allocated by the encoder        pkt.size = 0;         for (j = 0; j < c->frame_size; j++) {            samples[2*j] = (int)(sin(t) * 10000);             for (k = 1; k < c->channels; k++)                samples[2*j + k] = samples[2*j];            t += tincr;        }        /* encode the samples */        ret = avcodec_encode_audio2(c, &pkt, frame, &got_output);        if (ret < 0) {            fprintf(stderr, "error encoding audio frame\n");            exit(1);        }        if (got_output) {            fwrite(pkt.data, 1, pkt.size, f);            av_free_packet(&pkt);        }    }    fclose(f);     av_freep(&samples);    avcodec_free_frame(&frame);    avcodec_close(c);    av_free(c);} /* * 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 + FF_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 = avcodec_alloc_frame())) {                fprintf(stderr, "out of memory\n");                exit(1);            }        } else            avcodec_get_frame_defaults(decoded_frame);         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_close(c);    av_free(c);    avcodec_free_frame(&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 mpeg1 video 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= avcodec_alloc_frame();     /* 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_free_packet(&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_free_packet(&pkt);        }    }     /* add sequence end code to have a real mpeg file */    fwrite(endcode, 1, sizeof(endcode), f);    fclose(f);     avcodec_close(c);    av_free(c);    av_freep(&picture->data[0]);    avcodec_free_frame(&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 + FF_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, FF_INPUT_BUFFER_PADDING_SIZE);     printf("Video decoding\n");     /* find the mpeg1 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= avcodec_alloc_frame();     if(codec->capabilities&CODEC_CAP_TRUNCATED)        c->flags|= 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) {

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