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avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet), the frameFinished is 0 most of the time why ?

26 mai 2014, par Whoami
I received a packet from rtsp by av_read_frame and decode it through
```
avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet)
```
After decoding i am checking the value of frameFinished.

Most of the time i get the value of frameFinished is zero. May be around 50% of the packet.

Could you kindly hint me what could be the reason ?

is this issue in any way related to 'I', 'P', 'B' packet types ?

ffmpeg libx264 AVCodecContext settings

21 mai 2014, par integra753

I am using a recent windows (Jan 2011) ffmpeg build and trying to record video in H264. It is recording fine in MPEG4 using the following settings:

c->codec_id = CODEC_ID_MPEG4;
c->codec_type = AVMEDIA_TYPE_VIDEO;
c->width = VIDEO_WIDTH;
c->height = VIDEO_HEIGHT;
c->bit_rate = c->width * c->height * 4;
c->time_base.den = FRAME_RATE;
c->time_base.num = 1;
c->gop_size = 12;
c->pix_fmt = PIX_FMT_YUV420P;

Simply changing CODEC Id to H264 causes avcodec_open() to fail (-1). I found a list of possible settings Encoding h.264 with libavcodec/x264. I have tried these, without setting pix_fmt, avcodec_open() still fails but if I additionally set c->pix_fmt = PIX_FMT_YUV420P; then I get a divide by zero exception.

I then came across a few posts on here that say I should set nothing (with exception of code_id, codec_type, width, height and perhaps bit_rate and pix_fmt) as the library now chooses the best settings itself. I have tried various combinations, still avcode_open() fails.

Does anyone have some advice on what to do or some settings that are current?

Thanks.

Here are one set of H264 settings which give the issue I describe:

static AVStream* AddVideoStream(AVFormatContext *pOutputFmtCtx, 
int frameWidth, int frameHeight, int fps)
{
AVCodecContext* ctx;
AVStream* stream;

stream = av_new_stream(pOutputFmtCtx, 0);
if (!stream) 
{
    return NULL;
}

ctx = stream->codec;

ctx->codec_id = pOutputFmtCtx->oformat->video_codec; //CODEC_ID_H264
ctx->codec_type = AVMEDIA_TYPE_VIDEO;
ctx->width = frameWidth;             //704
ctx->height = frameHeight;           //576
ctx->bit_rate = frameWidth * frameHeight * 4;

ctx->coder_type = 1;  // coder = 1
ctx->flags|=CODEC_FLAG_LOOP_FILTER;   // flags=+loop
ctx->me_cmp|= 1;  // cmp=+chroma, where CHROMA = 1
ctx->partitions|=X264_PART_I8X8+X264_PART_I4X4+X264_PART_P8X8+X264_PART_B8X8; // partitions=+parti8x8+parti4x4+partp8x8+partb8x8
ctx->me_method=ME_HEX;    // me_method=hex
ctx->me_subpel_quality = 7;   // subq=7
ctx->me_range = 16;   // me_range=16
ctx->gop_size = 250;  // g=250
ctx->keyint_min = 25; // keyint_min=25
ctx->scenechange_threshold = 40;  // sc_threshold=40
ctx->i_quant_factor = 0.71; // i_qfactor=0.71
ctx->b_frame_strategy = 1;  // b_strategy=1
ctx->qcompress = 0.6; // qcomp=0.6
ctx->qmin = 10;   // qmin=10
ctx->qmax = 51;   // qmax=51
ctx->max_qdiff = 4;   // qdiff=4
ctx->max_b_frames = 3;    // bf=3
ctx->refs = 3;    // refs=3
ctx->directpred = 1;  // directpred=1
ctx->trellis = 1; // trellis=1
       ctx->flags2|=CODEC_FLAG2_BPYRAMID+CODEC_FLAG2_MIXED_REFS+CODEC_FLAG2_WPRED+CODEC_FLAG2_8X8DCT+CODEC_FLAG2_FASTPSKIP;  // flags2=+bpyramid+mixed_refs+wpred+dct8x8+fastpskip
ctx->weighted_p_pred = 2; // wpredp=2
// libx264-main.ffpreset preset
ctx->flags2|=CODEC_FLAG2_8X8DCT;
ctx->flags2^=CODEC_FLAG2_8X8DCT;    // flags2=-dct8x8

// if set this get divide by 0 error on avcodec_open()
// if don't set it get -1 error on avcodec_open()
//ctx->pix_fmt = PIX_FMT_YUV420P; 

return stream;

}

How to use x264 for encoding with ffmpeg ?

21 mai 2014, par mmmaaak

I tryed to use ffmpeg for encoding video/ But it fails on initialization of AVCodecContext annd AVCodec. What I do:

_codec = avcodec_find_encoder(CODEC_ID_H264);
_codecContext = avcodec_alloc_context3(_codec);
_codecContext->coder_type = 0;
_codecContext->me_cmp|= 1;
_codecContext->me_method=ME_HEX;
_codecContext->me_subpel_quality = 0;
_codecContext->me_range = 16;
_codecContext->gop_size = 12;
_codecContext->scenechange_threshold = 40;
_codecContext->i_quant_factor = 0.71;
_codecContext->b_frame_strategy = 1;
_codecContext->qcompress = 0.5;
_codecContext->qmin = 2;
_codecContext->qmax = 31;
_codecContext->max_qdiff = 4;
_codecContext->max_b_frames = 3;
_codecContext->refs = 3;
_codecContext->trellis = 1;
_codecContext->width = format.biWidth;
_codecContext->height = format.biHeight;
_codecContext->time_base.num = 1;
_codecContext->time_base.den = 30;
_codecContext->pix_fmt = PIX_FMT_YUV420P; 
_codecContext->chromaoffset = 0;
_codecContext->thread_count =1;
_codecContext->bit_rate = (int)(128000.f * 0.80f);
_codecContext->bit_rate_tolerance = (int) (128000.f * 0.20f);
int error = avcodec_open2(_codecContext, _codec, NULL);
if(error<   )
{
    std::cout<<"Open codec fail. Error "<code>

In such way ii fails on avopen_codec2() with:

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xae1fdb70 (LWP 30675)]
0xb2eb2cbb in x264_param_default () from /usr/lib/libx264.so.120

If i comment all AVCodecContext parameters settins - I have :

[libx264 @ 0xac75edd0] invalid width x height (0x0)

And avcodec_open retunrs negative value. Which steps, I'm doing, are wrong?

Thanks for any help (ffmpeg 0.10 && libx264 daily snapshot for yesterday)

libx264 x264_nal_encode overflowing

8 mai 2014, par Ulterior

My libH264 app is performing encoding of incomming camera data, but it keeps accumulating data and slows down the more encode operations it performs. Any idea's why is this happening?

Variables are allocated at the start of a program. Is my sequence incorrect? I suspect I have to reinitilize some structure, but I cant find out how to do it...

Here is part of my code in camera thread:

    int nWidth = 640;
    int nHeight = 480;

fill YUV data

    memcpy(p264Pic->img.plane[0],pic.buffer,nWidth*nHeight);  
    memcpy(p264Pic->img.plane[1],pic.buffer+nWidth*nHeight,nWidth*nHeight/4);  
    memcpy(p264Pic->img.plane[2],pic.buffer+nWidth*nHeight*5/4,nWidth*nHeight/4);

fill PTS

    p264Pic->i_pts = high_resolution_timer_tick_count();

//          if( nFramsInPack % 8 == 0){
//           p264Pic->i_type = X264_TYPE_I;
//          }else{
             p264Pic->i_type = X264_TYPE_AUTO;
//      }

    if( x264_encoder_encode( p264Handle, &p264Nal, &i264Nal, p264Pic ,&pic_out) < 0 ) {  
                fprintf( stderr, "x264_encoder_encode failed/n" );  
    }  
    printf("i264Nal %d\n", i264Nal );

    for( int i = 0; i < i264Nal; i++ )  
    {
     printf( "nal pass %d\n", i );
     int i_data = 1024*32;  

     printf( "nal encode\n" );

     x264_nal_encode( p264Handle, pNal, &p264Nal[i] );

     printf( "after nal encode\n" );

     int i_size = p264Nal[i].i_payload;     

     printf("i_size %d\n", i_size );

     if( i_size > 0 ) {  

       if ((pNal[4]&0x60)==0) {  
           continue;  
       }  
       if (pNal[4]==0x67) {  
           continue;  
       }  
       if (pNal[4]==0x68) {  
           continue;  
       }  
       memmove(pNal,pNal+4,i_size-4);  
       pNal+=i_size-4;  
     }  
     else if( i_size < 0 ) {  
       fprintf( stderr,"need to increase buffer size (size=%d)/n", -i_size );  
     }  
    }

Pack data to RTMP

    unsigned int nSize=pNal-szNalBuffer;  
    packet.m_nBodySize=nSize+9;  
    if (i264Nal>1) {  
     szBodyBuffer[ 0]=0x17;  
    }  
    else {  
     szBodyBuffer[ 0]=0x27;  
    }  
    put_be32((char *)szBodyBuffer+5,nSize);  
    memcpy(szBodyBuffer+9,szNalBuffer,pNal-szNalBuffer);  

    printf( "rtmp send packet\n" );

    RTMP_SendPacket(rtmp,&packet,0);  
    newTick=high_resolution_timer_tick_count();  
    packet.m_headerType = RTMP_PACKET_SIZE_MEDIUM;  
    packet.m_nTimeStamp+=newTick-oldTick;  
    oldTick=newTick;

Here is the output of my app:

i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 0
rtmp send packet
i264Nal 4
nal pass 0
nal encode
after nal encode
i_size 36
nal pass 1
nal encode
after nal encode
i_size 15
nal pass 2
nal encode
after nal encode
i_size 632
nal pass 3
nal encode
after nal encode
i_size 7151
rtmp send packet
i264Nal 1
nal pass 0
nal encode
after nal encode
i_size 8136
rtmp send packet
i264Nal 1
nal pass 0
nal encode
after nal encode
i_size 28955
rtmp send packet
^CThe pthread schedule_do end
^Cthread is end
i264Nal 1
nal pass 0
nal encode
after nal encode

ffmpeg syntax has changed

8 mai 2014, par Budgierless
Just like what was talked about in this post: FFmpeg cannot recognize a preset even though it does exsist Ubuntu 12.04

I have help, with deblockalpha which has been depreciated from ffmpeg for along time, i am no good with all this coding business, but would like someone to tell me how i can fix this outdated syntax, as i am getting this error:

Unrecognized option 'deblockalpha' Failed to set value '0' for option 'deblockalpha'

please see code below and advise?
```
$ffmpeg -i $input -r 30 -vcodec libx264 -s 512x288 -aspect 16:9 -b 1550k -maxrate 1800k -bufsize 4M -bt 1600k -flags +loop -cmp +chroma -deblockalpha 0 -deblockbeta 0 -refs 1 -coder 0 -me_method full -me_range 16 -subq 5 -partitions +parti4x4+parti8x8+partp8x8 -g 250 -keyint_min 25 -level 30 -trellis 2 -sc_threshold 40 -i_qfactor 0.71 -acodec libfaac -ab 128k -ar 44100 -ac 2 $addpre $output";
```
thanks

1 | ... | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | ... | 88

Newest 'libx264' Questions - Stack Overflow

Les articles publiés sur le site

avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet), the frameFinished is 0 most of the time why ?

ffmpeg libx264 AVCodecContext settings

How to use x264 for encoding with ffmpeg ?

libx264 x264_nal_encode overflowing

ffmpeg syntax has changed

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