Çıktı ffmpeg ile RTSP akışı

Question

Uygulamamdan bir medya sunucusuna (bu durumda wowza) bir video akışı göndermek için ffmpeg kitaplıklarını kullanmaya çalışıyorum. Ben ters yapmak mümkün olmuştur ve bir RTSP akışı tüketmek ancak bir RTSP akışı yazma bazı sorunlar yaşıyorum var.

Ben birkaç örnek buldum ve ilgili bitleri kullanmaya çalıştılar. Kod aşağıda. Elimden geldiğince basitleştirdim. Ben sadece işleyebilir wowza sunucu ve hangi tek bir H264 bit akışı göndermek istiyorum.

Bir paket göndermeye çalıştığımda av_interleaved_write_frame işlevinde her zaman "Sıfır olarak tamsayı bölme" özel durumu alıyorum. İstisna, paket zaman damgalarının doğru ayarlanmadığı ile ilgili gibi görünüyor. Ben farklı değerler denedim ve bazı suni değerler ayarlayarak istisna geçmiş olsun ama sonra yazma çağrı başarısız olur.

#include <iostream> 
#include <fstream> 
#include <sstream> 
#include <cstring> 

#include "stdafx.h" 
#include "windows.h" 

extern "C" 
{ 
    #include <libavcodec\avcodec.h> 
    #include <libavformat\avformat.h> 
    #include <libavformat\avio.h> 
    #include <libswscale\swscale.h> 
} 

using namespace std; 

static int video_is_eof; 

#define STREAM_DURATION 50.0 
#define STREAM_FRAME_RATE 25 /* 25 images/s */ 
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */ 
#define VIDEO_CODEC_ID CODEC_ID_H264 

static int sws_flags = SWS_BICUBIC; 

/* video output */ 
static AVFrame *frame; 
static AVPicture src_picture, dst_picture; 
static int frame_count; 

static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt) 
{ 
    /* rescale output packet timestamp values from codec to stream timebase */ 
    pkt->pts = av_rescale_q_rnd(pkt->pts, *time_base, st->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX)); 
    pkt->dts = av_rescale_q_rnd(pkt->dts, *time_base, st->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX)); 
    pkt->duration = av_rescale_q(pkt->duration, *time_base, st->time_base); 

    pkt->stream_index = st->index; 

    // Exception occurs here. 
    return av_interleaved_write_frame(fmt_ctx, pkt); 
} 

/* Add an output stream. */ 
static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id) 
{ 
    AVCodecContext *c; 
    AVStream *st; 

    /* find the encoder */ 
    *codec = avcodec_find_encoder(codec_id); 
    if (!(*codec)) { 
     fprintf(stderr, "Could not find encoder for '%s'\n", avcodec_get_name(codec_id)); 
     exit(1); 
    } 

    st = avformat_new_stream(oc, *codec); 
    if (!st) { 
     fprintf(stderr, "Could not allocate stream\n"); 
     exit(1); 
    } 

    st->id = oc->nb_streams - 1; 
    c = st->codec; 
    c->codec_id = codec_id; 
    c->bit_rate = 400000; 
    c->width = 352; 
    c->height = 288; 
    c->time_base.den = STREAM_FRAME_RATE; 
    c->time_base.num = 1; 
    c->gop_size = 12; /* emit one intra frame every twelve frames at most */ 
    c->pix_fmt = STREAM_PIX_FMT; 

    return st; 
} 

static void open_video(AVFormatContext *oc, AVCodec *codec, AVStream *st) 
{ 
    int ret; 
    AVCodecContext *c = st->codec; 

    /* open the codec */ 
    ret = avcodec_open2(c, codec, NULL); 
    if (ret < 0) { 
     fprintf(stderr, "Could not open video codec: "); 
     exit(1); 
    } 

    /* allocate and init a re-usable frame */ 
    frame = av_frame_alloc(); 
    if (!frame) { 
     fprintf(stderr, "Could not allocate video frame\n"); 
     exit(1); 
    } 
    frame->format = c->pix_fmt; 
    frame->width = c->width; 
    frame->height = c->height; 

    /* Allocate the encoded raw picture. */ 
    ret = avpicture_alloc(&dst_picture, c->pix_fmt, c->width, c->height); 
    if (ret < 0) { 
     fprintf(stderr, "Could not allocate picture: "); 
     exit(1); 
    } 

    /* copy data and linesize picture pointers to frame */ 
    *((AVPicture *)frame) = dst_picture; 
} 

/* Prepare a dummy image. */ 
static void fill_yuv_image(AVPicture *pict, int frame_index, int width, int height) 
{ 
    int x, y, i; 

    i = frame_index; 

    /* Y */ 
    for (y = 0; y < height; y++) 
     for (x = 0; x < width; x++) 
      pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3; 

    /* Cb and Cr */ 
    for (y = 0; y < height/2; y++) { 
     for (x = 0; x < width/2; x++) { 
      pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2; 
      pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5; 
     } 
    } 
} 

static void write_video_frame(AVFormatContext *oc, AVStream *st, int flush) 
{ 
    int ret; 
    AVCodecContext *c = st->codec; 

    if (!flush) { 
     fill_yuv_image(&dst_picture, frame_count, c->width, c->height); 
    } 

    AVPacket pkt = { 0 }; 
    int got_packet; 
    av_init_packet(&pkt); 

    /* encode the image */ 
    frame->pts = frame_count; 
    ret = avcodec_encode_video2(c, &pkt, flush ? NULL : frame, &got_packet); 
    if (ret < 0) { 
     fprintf(stderr, "Error encoding video frame:"); 
     exit(1); 
    } 
    /* If size is zero, it means the image was buffered. */ 

    if (got_packet) { 
     ret = write_frame(oc, &c->time_base, st, &pkt); 
    } 
    else { 
     if (flush) { 
      video_is_eof = 1; 
     } 
     ret = 0; 
    } 

    if (ret < 0) { 
     fprintf(stderr, "Error while writing video frame: "); 
     exit(1); 
    } 
    frame_count++; 
} 

static void close_video(AVFormatContext *oc, AVStream *st) 
{ 
    avcodec_close(st->codec); 
    av_free(src_picture.data[0]); 
    av_free(dst_picture.data[0]); 
    av_frame_free(&frame); 
} 

int _tmain(int argc, _TCHAR* argv[]) 
{ 
    printf("starting...\n"); 

    const char *filename = "rtsp://test:password@192.168.33.19:1935/ffmpeg/0"; 

    AVOutputFormat *fmt; 
    AVFormatContext *oc; 
    AVStream *video_st; 
    AVCodec *video_codec; 
    double video_time; 
    int flush, ret; 

    /* Initialize libavcodec, and register all codecs and formats. */ 
    av_register_all(); 
    avformat_network_init(); 

    AVOutputFormat* oFmt = av_oformat_next(NULL); 
    while (oFmt) { 
     if (oFmt->video_codec == VIDEO_CODEC_ID) { 
      break; 
     } 
     oFmt = av_oformat_next(oFmt); 
    } 

    if (!oFmt) { 
     printf("Could not find the required output format.\n"); 
     exit(1); 
    } 

    /* allocate the output media context */ 
    avformat_alloc_output_context2(&oc, oFmt, "rtsp", filename); 

    if (!oc) { 
     printf("Could not set the output media context.\n"); 
     exit(1); 
    } 

    fmt = oc->oformat; 
    if (!fmt) { 
     printf("Could not create the output format.\n"); 
     exit(1); 
    } 

    video_st = NULL; 

    cout << "Codec = " << avcodec_get_name(fmt->video_codec) << endl; 
    if (fmt->video_codec != AV_CODEC_ID_NONE) 
    { 
     video_st = add_stream(oc, &video_codec, fmt->video_codec); 
    } 

    /* Now that all the parameters are set, we can open the video codec and allocate the necessary encode buffers. */ 
    if (video_st) { 
     open_video(oc, video_codec, video_st); 
    } 

    av_dump_format(oc, 0, filename, 1); 
    char errorBuff[80]; 

    if (!(fmt->flags & AVFMT_NOFILE)) { 
     ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE); 
     if (ret < 0) { 
      fprintf(stderr, "Could not open outfile '%s': %s", filename, av_make_error_string(errorBuff, 80, ret)); 
      return 1; 
     } 
    } 

    flush = 0; 
    while (video_st && !video_is_eof) { 
     /* Compute current video time. */ 
     video_time = (video_st && !video_is_eof) ? video_st->pts.val * av_q2d(video_st->time_base) : INFINITY; 

     if (!flush && (!video_st || video_time >= STREAM_DURATION)) { 
      flush = 1; 
     } 

     if (video_st && !video_is_eof) { 
      write_video_frame(oc, video_st, flush); 
     } 
    } 

    if (video_st) { 
     close_video(oc, video_st); 
    } 

    if ((fmt->flags & AVFMT_NOFILE)) { 
     avio_close(oc->pb); 
    } 

    avformat_free_context(oc); 

    printf("finished.\n"); 

    getchar(); 

    return 0; 
} 

Paket zaman damgalarının nasıl başarılı bir şekilde ayarlanabileceği konusunda herhangi bir kavrayış var mı?

Answer 1

Windows örneğimde ffmpeg oluşturup av_interleaved_write_frame çağrısında hata ayıklamayı yaparak tamsayı bölümünü sıfırla çözdüm. Bu, istisnaya neden olan video akışı nesnesinde ayarlanmayan pts olduğunu ortaya çıkarır.

video_st->pts.val += av_rescale_q(1, video_st->codec->time_base, video_st->time_base); 

İşte ffmpeg en RTSP boru hattı üzerinden bir Wowza sunucusuna bir H264 kodlanmış kukla akım elde etmek için çalışan bir örnek var: Ana işlevi ise döngü için aşağıdaki satırı ekleme

sorun giderildi.

// Roughly based on: https://ffmpeg.org/doxygen/trunk/muxing_8c-source.html 

#include <chrono> 
#include <thread> 
#include <tchar.h> 

extern "C" 
{ 
    #include <libavcodec\avcodec.h> 
    #include <libavformat\avformat.h> 
    #include <libavformat\avio.h> 
    #include <libswscale\swscale.h> 
    #include <libavutil\time.h> 
} 

#pragma comment(lib,"libavformat/libavformat.a") 
#pragma comment(lib,"libavcodec/libavcodec.a") 
#pragma comment(lib,"libavutil/libavutil.a") 
#pragma comment(lib,"libswscale/libswscale.a") 
#pragma comment(lib,"x264.lib") 
#pragma comment(lib,"libswresample/libswresample.a") 

using namespace std; 

static int video_is_eof; 

#define STREAM_DURATION 20 
#define STREAM_FRAME_RATE 25 /* 25 images/s */ 
#define STREAM_PIX_FMT AV_PIX_FMT_YUV420P /* default pix_fmt */ //AV_PIX_FMT_NV12; 
#define VIDEO_CODEC_ID CODEC_ID_H264 

/* video output */ 
static AVFrame *frame; 
static AVPicture src_picture, dst_picture; 

/* Add an output stream. */ 
static AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id) 
{ 
    AVCodecContext *c; 
    AVStream *st; 

    /* find the encoder */ 
    *codec = avcodec_find_encoder(codec_id); 
    if (!(*codec)) { 
     av_log(NULL, AV_LOG_ERROR, "Could not find encoder for '%s'.\n", avcodec_get_name(codec_id)); 
    } 
    else { 
     st = avformat_new_stream(oc, *codec); 
     if (!st) { 
      av_log(NULL, AV_LOG_ERROR, "Could not allocate stream.\n"); 
     } 
     else { 
      st->id = oc->nb_streams - 1; 
      st->time_base.den = st->pts.den = 90000; 
      st->time_base.num = st->pts.num = 1; 

      c = st->codec; 
      c->codec_id = codec_id; 
      c->bit_rate = 400000; 
      c->width = 352; 
      c->height = 288; 
      c->time_base.den = STREAM_FRAME_RATE; 
      c->time_base.num = 1; 
      c->gop_size = 12; /* emit one intra frame every twelve frames at most */ 
      c->pix_fmt = STREAM_PIX_FMT; 
     } 
    } 

    return st; 
} 

static int open_video(AVFormatContext *oc, AVCodec *codec, AVStream *st) 
{ 
    int ret; 
    AVCodecContext *c = st->codec; 

    /* open the codec */ 
    ret = avcodec_open2(c, codec, NULL); 
    if (ret < 0) { 
     av_log(NULL, AV_LOG_ERROR, "Could not open video codec.\n", avcodec_get_name(c->codec_id)); 
    } 
    else { 

     /* allocate and init a re-usable frame */ 
     frame = av_frame_alloc(); 
     if (!frame) { 
      av_log(NULL, AV_LOG_ERROR, "Could not allocate video frame.\n"); 
      ret = -1; 
     } 
     else { 
      frame->format = c->pix_fmt; 
      frame->width = c->width; 
      frame->height = c->height; 

      /* Allocate the encoded raw picture. */ 
      ret = avpicture_alloc(&dst_picture, c->pix_fmt, c->width, c->height); 
      if (ret < 0) { 
       av_log(NULL, AV_LOG_ERROR, "Could not allocate picture.\n"); 
      } 
      else { 
       /* copy data and linesize picture pointers to frame */ 
       *((AVPicture *)frame) = dst_picture; 
      } 
     } 
    } 

    return ret; 
} 

/* Prepare a dummy image. */ 
static void fill_yuv_image(AVPicture *pict, int frame_index, int width, int height) 
{ 
    int x, y, i; 

    i = frame_index; 

    /* Y */ 
    for (y = 0; y < height; y++) 
     for (x = 0; x < width; x++) 
      pict->data[0][y * pict->linesize[0] + x] = x + y + i * 3; 

    /* Cb and Cr */ 
    for (y = 0; y < height/2; y++) { 
     for (x = 0; x < width/2; x++) { 
      pict->data[1][y * pict->linesize[1] + x] = 128 + y + i * 2; 
      pict->data[2][y * pict->linesize[2] + x] = 64 + x + i * 5; 
     } 
    } 
} 

static int write_video_frame(AVFormatContext *oc, AVStream *st, int frameCount) 
{ 
    int ret = 0; 
    AVCodecContext *c = st->codec; 

    fill_yuv_image(&dst_picture, frameCount, c->width, c->height); 

    AVPacket pkt = { 0 }; 
    int got_packet; 
    av_init_packet(&pkt); 

    /* encode the image */ 
    frame->pts = frameCount; 
    ret = avcodec_encode_video2(c, &pkt, frame, &got_packet); 
    if (ret < 0) { 
     av_log(NULL, AV_LOG_ERROR, "Error encoding video frame.\n"); 
    } 
    else { 
     if (got_packet) { 
      pkt.stream_index = st->index; 
      pkt.pts = av_rescale_q_rnd(pkt.pts, c->time_base, st->time_base, AVRounding(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX)); 
      ret = av_write_frame(oc, &pkt); 

      if (ret < 0) { 
       av_log(NULL, AV_LOG_ERROR, "Error while writing video frame.\n"); 
      } 
     } 
    } 

    return ret; 
} 

int _tmain(int argc, _TCHAR* argv[]) 
{ 
    printf("starting...\n"); 

    const char *url = "rtsp://test:password@192.168.33.19:1935/ffmpeg/0"; 
    //const char *url = "rtsp://192.168.33.19:1935/ffmpeg/0"; 

    AVFormatContext *outContext; 
    AVStream *video_st; 
    AVCodec *video_codec; 
    int ret = 0, frameCount = 0; 

    av_log_set_level(AV_LOG_DEBUG); 
    //av_log_set_level(AV_LOG_TRACE); 

    av_register_all(); 
    avformat_network_init(); 

    avformat_alloc_output_context2(&outContext, NULL, "rtsp", url); 

    if (!outContext) { 
     av_log(NULL, AV_LOG_FATAL, "Could not allocate an output context for '%s'.\n", url); 
     goto end; 
    } 

    if (!outContext->oformat) { 
     av_log(NULL, AV_LOG_FATAL, "Could not create the output format for '%s'.\n", url); 
     goto end; 
    } 

    video_st = add_stream(outContext, &video_codec, VIDEO_CODEC_ID); 

    /* Now that all the parameters are set, we can open the video codec and allocate the necessary encode buffers. */ 
    if (video_st) { 
     av_log(NULL, AV_LOG_DEBUG, "Video stream codec %s.\n ", avcodec_get_name(video_st->codec->codec_id)); 

     ret = open_video(outContext, video_codec, video_st); 
     if (ret < 0) { 
      av_log(NULL, AV_LOG_FATAL, "Open video stream failed.\n"); 
      goto end; 
     } 
    } 
    else { 
     av_log(NULL, AV_LOG_FATAL, "Add video stream for the codec '%s' failed.\n", avcodec_get_name(VIDEO_CODEC_ID)); 
     goto end; 
    } 

    av_dump_format(outContext, 0, url, 1); 

    ret = avformat_write_header(outContext, NULL); 
    if (ret != 0) { 
     av_log(NULL, AV_LOG_ERROR, "Failed to connect to RTSP server for '%s'.\n", url); 
     goto end; 
    } 

    printf("Press any key to start streaming...\n"); 
    getchar(); 

    auto startSend = std::chrono::system_clock::now(); 

    while (video_st) { 
     frameCount++; 
     auto startFrame = std::chrono::system_clock::now(); 

     ret = write_video_frame(outContext, video_st, frameCount); 

     if (ret < 0) { 
      av_log(NULL, AV_LOG_ERROR, "Write video frame failed.\n", url); 
      goto end; 
     } 

     auto streamDuration = std::chrono::duration_cast<chrono::milliseconds>(std::chrono::system_clock::now() - startSend).count(); 

     printf("Elapsed time %ldms, video stream pts %ld.\n", streamDuration, video_st->pts.val); 

     if (streamDuration/1000.0 > STREAM_DURATION) { 
      break; 
     } 
     else { 
      auto frameDuration = std::chrono::duration_cast<chrono::milliseconds>(std::chrono::system_clock::now() - startFrame).count(); 
      std::this_thread::sleep_for(std::chrono::milliseconds((long)(1000.0/STREAM_FRAME_RATE - frameDuration))); 
     } 
    } 

    if (video_st) { 
     avcodec_close(video_st->codec); 
     av_free(src_picture.data[0]); 
     av_free(dst_picture.data[0]); 
     av_frame_free(&frame); 
    } 

    avformat_free_context(outContext); 

end: 
    printf("finished.\n"); 

    getchar(); 

    return 0; 
}