ffmpeg将连续的h264分割为单帧

妖狐艹你老母 2022-09-05 06:10 223阅读 0赞

http://ffmpeg.org/doxygen/trunk/decode\_video\_8c-example.html

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    decode_video.c
    /* * Copyright (c) 2001 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */
     
    /** * @file * video decoding with libavcodec API example * * @example decode_video.c */
     
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
     
    #include <libavcodec/avcodec.h>
     
    #define INBUF_SIZE 4096
     
    static void pgm_save(unsigned char *buf, int wrap, int xsize, int ysize,
                         char *filename)
    { 
        FILE *f;
        int i;
     
        f = fopen(filename,"wb");
        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 decode(AVCodecContext *dec_ctx, AVFrame *frame, AVPacket *pkt,
                       const char *filename)
    { 
        char buf[1024];
        int ret;
     
        ret = avcodec_send_packet(dec_ctx, pkt);
        if (ret < 0) { 
            fprintf(stderr, "Error sending a packet for decoding\n");
            exit(1);
        }
     
        while (ret >= 0) { 
            ret = avcodec_receive_frame(dec_ctx, frame);
            if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                return;
            else if (ret < 0) { 
                fprintf(stderr, "Error during decoding\n");
                exit(1);
            }
     
            printf("saving frame %3d\n", dec_ctx->frame_number);
            fflush(stdout);
     
            /* the picture is allocated by the decoder. no need to free it */
            snprintf(buf, sizeof(buf), "%s-%d", filename, dec_ctx->frame_number);
            pgm_save(frame->data[0], frame->linesize[0],
                     frame->width, frame->height, buf);
        }
    }
     
    int main(int argc, char **argv)
    { 
        const char *filename, *outfilename;
        const AVCodec *codec;
        AVCodecParserContext *parser;
        AVCodecContext *c= NULL;
        FILE *f;
        AVFrame *frame;
        uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
        uint8_t *data;
        size_t   data_size;
        int ret;
        AVPacket *pkt;
     
        if (argc <= 2) { 
            fprintf(stderr, "Usage: %s <input file> <output file>\n"
                    "And check your input file is encoded by mpeg1video please.\n", argv[0]);
            exit(0);
        }
        filename    = argv[1];
        outfilename = argv[2];
     
        pkt = av_packet_alloc();
        if (!pkt)
            exit(1);
     
        /* 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);
     
        /* find the MPEG-1 video decoder */
        codec = avcodec_find_decoder(AV_CODEC_ID_MPEG1VIDEO);
        if (!codec) { 
            fprintf(stderr, "Codec not found\n");
            exit(1);
        }
     
        parser = av_parser_init(codec->id);
        if (!parser) { 
            fprintf(stderr, "parser not found\n");
            exit(1);
        }
     
        c = avcodec_alloc_context3(codec);
        if (!c) { 
            fprintf(stderr, "Could not allocate video codec context\n");
            exit(1);
        }
     
        /* 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);
        }
     
        f = fopen(filename, "rb");
        if (!f) { 
            fprintf(stderr, "Could not open %s\n", filename);
            exit(1);
        }
     
        frame = av_frame_alloc();
        if (!frame) { 
            fprintf(stderr, "Could not allocate video frame\n");
            exit(1);
        }
     
        while (!feof(f)) { 
            /* read raw data from the input file */
            data_size = fread(inbuf, 1, INBUF_SIZE, f);
            if (!data_size)
                break;
     
            /* use the parser to split the data into frames */
            data = inbuf;
            while (data_size > 0) { 
                ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
                                       data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
                if (ret < 0) { 
                    fprintf(stderr, "Error while parsing\n");
                    exit(1);
                }
                data      += ret;
                data_size -= ret;
     
                if (pkt->size)
                    decode(c, frame, pkt, outfilename);
            }
        }
     
        /* flush the decoder */
        decode(c, frame, NULL, outfilename);
     
        fclose(f);
     
        av_parser_close(parser);
        avcodec_free_context(&c);
        av_frame_free(&frame);
        av_packet_free(&pkt);
     
        return 0;
    }
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