Ticket #6627: ffmpegbug.cpp

extern "C" {
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/avutil.h>
};
#include <stdio.h>

int main()
{
    av_register_all();
    AVFormatContext* ctx = 0;
    if (avformat_open_input(&ctx, "test.mp4", NULL, NULL) != 0)
    {
        perror("open file failed");
        exit(1);
    }

    AVCodec* codec = 0;
    int atrack = av_find_best_stream(ctx, AVMEDIA_TYPE_AUDIO, -1, -1, &codec, 0);
    if (atrack < 0)
    {
        perror("fail to find audio stream");
        exit(1);
    }

    AVCodecContext* codecCtx = avcodec_alloc_context3(codec);
    if (!codecCtx)
    {
        perror("fail to alloc codec context");
        exit(1);
    }

    if (avcodec_parameters_to_context(codecCtx, ctx->streams[atrack]->codecpar) < 0)
    {
        perror("fail to set decoder param");
        exit(1);
    }

    if (avcodec_open2(codecCtx, codec, NULL) != 0)
    {
        perror("fail to open codec");
        exit(1);
    }

    for (int rep = 0; rep < 2; ++rep)
    {
        if (rep > 0 && av_seek_frame(ctx, atrack, -1020, AVSEEK_FLAG_BACKWARD) < 0)
        {
            perror("fail to seek file");
            exit(1);
        }
        avcodec_flush_buffers(codecCtx);

        for (;;)
        {
            AVPacket pkt;
            av_init_packet(&pkt);
            int ret = av_read_frame(ctx, &pkt);

            if (ret == AVERROR_EOF)
                break;
            else if (ret < 0)
            {
                perror("read packet error");
                exit(1);
            }

            if (pkt.pts == -1020)
            {
                printf("packet of pts=-1020 is %d bytes\n", pkt.size);

                avcodec_flush_buffers(codecCtx);
            }

            if (pkt.stream_index == atrack)
            {
                AVFrame* frame = av_frame_alloc();
                ret = avcodec_send_packet(codecCtx, &pkt);
                if (ret == 0)
                {
                    ret = avcodec_receive_frame(codecCtx, frame);
                    if (ret == 0)
                    {
                        if (pkt.pts == -1020)
                        {
                            printf("decode packet of pts=-1020 and got outputed frame\n");
                        }
                    }
                    else
                    {
                        if (pkt.pts == -1020)
                        {
                            printf("decode packet of pts=-1020 but not got outputed frame\n");
                        }
                    }
                }

                av_frame_free(&frame);
            }

            av_packet_unref(&pkt);
        }
    }

    avcodec_close(codecCtx);
    avformat_close_input(&ctx);

    return 0;
}