linux C h264文件转MP4文件 代码

以下是一个简单的示例程序，使用FFmpeg库将H.264视频文件转换为MP4文件：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libavutil/avutil.h>
#include <libavutil/opt.h>

int main(int argc, char *argv[]) {
    AVFormatContext *in_fmt_ctx = NULL, *out_fmt_ctx = NULL;
    AVCodecContext *codec_ctx = NULL;
    AVCodec *codec = NULL;
    AVPacket pkt;
    AVFrame *frame = NULL;
    int ret, i;

    if (argc < 3) {
        printf("Usage: %s <input_file.h264> <output_file.mp4>\n", argv[0]);
        return -1;
    }

    // Register all the codecs and formats
    av_register_all();

    // Open input file
    if ((ret = avformat_open_input(&in_fmt_ctx, argv[1], NULL, NULL)) < 0) {
        printf("Error: Could not open input file '%s'\n", argv[1]);
        return ret;
    }

    // Retrieve input stream information
    if ((ret = avformat_find_stream_info(in_fmt_ctx, NULL)) < 0) {
        printf("Error: Could not find stream information\n");
        return ret;
    }

    // Open output file
    if ((ret = avformat_alloc_output_context2(&out_fmt_ctx, NULL, NULL, argv[2])) < 0) {
        printf("Error: Could not create output context\n");
        return ret;
    }

    // Find codec
    codec = avcodec_find_encoder(AV_CODEC_ID_H264);
    if (!codec) {
        printf("Error: Could not find H.264 codec\n");
        return -1;
    }

    // Add video stream to output context
    AVStream *out_stream = avformat_new_stream(out_fmt_ctx, codec);
    if (!out_stream) {
        printf("Error: Could not create video stream\n");
        return -1;
    }
    out_stream->codecpar->codec_id = codec->id;

    // Copy codec parameters from input stream to output stream
    AVStream *in_stream = in_fmt_ctx->streams[0];
    codec_ctx = avcodec_alloc_context3(codec);
    avcodec_parameters_to_context(codec_ctx, in_stream->codecpar);
    codec_ctx->codec_tag = 0;
    if (out_fmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
        codec_ctx->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;

    // Open codec
    if ((ret = avcodec_open2(codec_ctx, codec, NULL)) < 0) {
        printf("Error: Could not open codec\n");
        return ret;
    }

    // Allocate frame
    frame = av_frame_alloc();
    if (!frame) {
        printf("Error: Could not allocate frame\n");
        return -1;
    }

    // Initialize packet
    av_init_packet(&pkt);
    pkt.data = NULL;
    pkt.size = 0;

    // Write header to output file
    avformat_write_header(out_fmt_ctx, NULL);

    // Read frames from input file and write to output file
    while (av_read_frame(in_fmt_ctx, &pkt) >= 0) {
        if (pkt.stream_index == 0) {
            // Decode packet
            ret = avcodec_send_packet(codec_ctx, &pkt);
            if (ret < 0) {
                printf("Error: Could not send packet for decoding\n");
                return ret;
            }
            while (ret >= 0) {
                ret = avcodec_receive_frame(codec_ctx, frame);
                if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                    break;
                else if (ret < 0) {
                    printf("Error: Could not decode frame\n");
                    return ret;
                }
                // Encode frame
                AVPacket enc_pkt;
                av_init_packet(&enc_pkt);
                enc_pkt.data = NULL;
                enc_pkt.size = 0;
                ret = avcodec_send_frame(codec_ctx, frame);
                if (ret < 0) {
                    printf("Error: Could not send frame for encoding\n");
                    return ret;
                }
                while (ret >= 0) {
                    ret = avcodec_receive_packet(codec_ctx, &enc_pkt);
                    if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF)
                        break;
                    else if (ret < 0) {
                        printf("Error: Could not encode packet\n");
                        return ret;
                    }
                    // Write packet to output file
                    av_write_frame(out_fmt_ctx, &enc_pkt);
                    av_packet_unref(&enc_pkt);
                }
            }
        }
        av_packet_unref(&pkt);
    }

    // Write trailer to output file
    av_write_trailer(out_fmt_ctx);

    // Free resources
    avcodec_free_context(&codec_ctx);
    av_frame_free(&frame);
    avformat_close_input(&in_fmt_ctx);
    avio_closep(&out_fmt_ctx->pb);
    avformat_free_context(out_fmt_ctx);

    return 0;
}

编译命令如下：

gcc -o h264_to_mp4 h264_to_mp4.c -lavformat -lavcodec -lavutil

使用示例：

./h264_to_mp4 input.h264 output.mp4