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• Revision 422d7bc918 : Relax maximum Q for extreme overshoot. Added code to relax the active maximum Q

  28 octobre 2014, par Paul Wilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Relax maximum Q for extreme overshoot.

  Added code to relax the active maximum Q in response
  to extreme local overshoot to reduce bandwidth peaks.

  The impact is small in metrics terms, but it this helps reduce
  bandwidth spikes and overall overshoot in a number of
  clips in our tests sets (especially the YT test set).

  In particular this should help prevent very big spikes where a clip
  is mainly easy but has a short hard section. In such a case a choice
  of maximum Q for the clip as a whole may allow us to hit the overall
  target rate but give some extreme spikes. The chunked encoding in YT
  mitigates this problem but it can show up where a longer clip is
  coded as a single chunk.

  Change-Id : I213d09950ccb8489d10adf00fda1e53235b39203

• Announcing Piwik will end PHP 5.3 support in six months (May 2015)

  20 octobre 2014, par Piwik Core Team — Community

  This post is an important announcement concerning all Piwik users who are using PHP 5.3.x to run Piwik. Piwik project will end support for PHP 5.3 in about six months in May 2015.

  All Piwik users are encouraged to upgrade to the latest PHP 5.5 or PHP 5.6 which brings huge benefits in terms of performance, memory usage, security and overall stability.

  Why is this important ?

  The PHP version 5.3 has reached its End of Life (EOL). Using this old version may expose you to security vulnerabilities and bugs that have been fixed in more recent versions of PHP.

  If you are still using PHP 5.3, note that Piwik will stop supporting this PHP version in May 2015. Around this time Piwik will start requiring PHP 5.4.

  Upgrade your PHP version before it’s too late !

  Learn more

  • PHP 5.3 End Of Life announcement
  • Piwik Requirements
  • How do I find out which version of PHP is running on my server ?

  Learn more about Piwik release schedule :

  • When is the next release of Piwik ?
  • How long is each release of Piwik maintained for ?
  • Piwik 3.0.0 release planning

• Ffmpeg set output format C++

  7 septembre 2022, par Turgut

  I made a program that encodes a video and I want to specify the format as h264 but I can't figure out how to do it. It automatically sets the format to mpeg4 and I can't change it. I got my code from ffmpegs official examples muxing.c and slightly edited it to fit my code (I haven't changed much especially did not touch the parts where it sets the format)

  


  Here is my code so for (I have trimmed down the code slightly, removing redundant parts)

  


  video_encoder.cpp :

  


  
video_encoder::video_encoder(int w, int h, float fps, unsigned int duration) 
 :width(w), height(h), STREAM_FRAME_RATE(fps), STREAM_DURATION(duration)
{
    std::string as_str = "./output/video.mp4";

    char* filename = const_cast(as_str.c_str());
    enc_inf.video_st, enc_inf.audio_st = (struct OutputStream) { 0 };
    enc_inf.video_st.next_pts = 1; 
    enc_inf.audio_st.next_pts = 1;
    enc_inf.encode_audio, enc_inf.encode_video = 0;
    int ret;
    int i;

    /* allocate the output media context */
    avformat_alloc_output_context2(&enc_inf.oc, NULL, NULL, filename);

    if (!enc_inf.oc) {
        std::cout << "FAILED" << std::endl;
        avformat_alloc_output_context2(&enc_inf.oc, NULL, "mpeg", filename);
    }

    enc_inf.fmt = enc_inf.oc->oformat;

    /* Add the audio and video streams using the default format codecs
     * and initialize the codecs. */
    if (enc_inf.fmt->video_codec != AV_CODEC_ID_NONE) {
        add_stream(&enc_inf.video_st, enc_inf.oc, &video_codec, enc_inf.fmt->video_codec);
        enc_inf.have_video = 1;
        enc_inf.encode_video = 1;
    }
    if (enc_inf.fmt->audio_codec != AV_CODEC_ID_NONE) {
        add_stream(&enc_inf.audio_st, enc_inf.oc, &audio_codec, enc_inf.fmt->audio_codec);
        enc_inf.have_audio = 1;
        enc_inf.encode_audio = 1;
    }

    /* Now that all the parameters are set, we can open the audio and
     * video codecs and allocate the necessary encode buffers. */
    if (enc_inf.have_video)
        open_video(enc_inf.oc, video_codec, &enc_inf.video_st, opt);

    if (enc_inf.have_audio)
        open_audio(enc_inf.oc, audio_codec, &enc_inf.audio_st, opt);
    av_dump_format(enc_inf.oc, 0, filename, 1);

    /* open the output file, if needed */
    if (!(enc_inf.fmt->flags & AVFMT_NOFILE)) {
        ret = avio_open(&enc_inf.oc->pb, filename, AVIO_FLAG_WRITE);
        if (ret < 0) {
            //VI_ERROR("Could not open '%s': %s\n", filename, ret);
            //return 1;
        }
    }

    /* Write the stream header, if any. */
    ret = avformat_write_header(enc_inf.oc, &opt);
    if (ret < 0) {
        VI_ERROR("Error occurred when opening output file:");
        //return 1;
    }
    
    //return 0;
}


/* Add an output stream. */
void video_encoder::add_stream(OutputStream *ost, AVFormatContext *oc,
                       const AVCodec **codec,
                       enum AVCodecID codec_id)
{
    AVCodecContext *c;
    int i;

    /* 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);
    }

    ost->tmp_pkt = av_packet_alloc();

    if (!ost->tmp_pkt) {
        fprintf(stderr, "Could not allocate AVPacket\n");
        exit(1);
    }

    ost->st = avformat_new_stream(oc, NULL);
    if (!ost->st) {
        fprintf(stderr, "Could not allocate stream\n");
        exit(1);
    }
    ost->st->id = oc->nb_streams-1;
    c = avcodec_alloc_context3(*codec);
    if (!c) {
        fprintf(stderr, "Could not alloc an encoding context\n");
        exit(1);
    }
    ost->enc = c;


    switch ((*codec)->type) {
    case AVMEDIA_TYPE_AUDIO:
        ...
        break;
    case AVMEDIA_TYPE_VIDEO:
        c->codec_id = codec_id;

        c->bit_rate = 10000;
        /* Resolution must be a multiple of two. */
        c->width    = width;
        c->height   = height;
        /* timebase: This is the fundamental unit of time (in seconds) in terms
         * of which frame timestamps are represented. For fixed-fps content,
         * timebase should be 1/framerate and timestamp increments should be
         * identical to 1. */
        ost->st->time_base = (AVRational){ 1, STREAM_FRAME_RATE }; // *frame_rate
        c->time_base       = ost->st->time_base;

        c->gop_size      = 7; /* emit one intra frame every twelve frames at most */
        //c->codec_id      = AV_CODEC_ID_H264;
        c->pix_fmt       = STREAM_PIX_FMT;
        //if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO) 
        //    c->max_b_frames = 2;
        if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
            /* Needed to avoid using macroblocks in which some coeffs overflow.
             * This does not happen with normal video, it just happens here as
             * the motion of the chroma plane does not match the luma plane. */
            c->mb_decision = 2;
        }

        if ((*codec)->pix_fmts){
            //c->pix_fmt = (*codec)->pix_fmts[0];
            std::cout << "NEW FORMAT : " << c->pix_fmt << std::endl;
        }

        break;
    }
     

    /* Some formats want stream headers to be separate. */
    if (oc->oformat->flags & AVFMT_GLOBALHEADER)
        c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}


  


  video_encoder.h

  


  
typedef struct OutputStream {
    AVStream *st;
    AVCodecContext *enc;

    /* pts of the next frame that will be generated */
    int64_t next_pts;
    int samples_count;

    AVFrame *frame;
    AVFrame *tmp_frame;

    AVPacket *tmp_pkt;

    float t, tincr, tincr2;

    struct SwsContext *sws_ctx;
    struct SwrContext *swr_ctx;
} OutputStream;

class video_encoder{
    private:
        typedef struct {
            OutputStream video_st, audio_st;
            const AVOutputFormat *fmt;
            AVFormatContext *oc;
            int have_video, have_audio, encode_video, encode_audio;
            std::string name;
        } encode_info;
    public:
        encode_info enc_inf;
        video_encoder(int w, int h, float fps, unsigned int duration);
        ~video_encoder();  
        ...
    private:
        ...
        void add_stream(OutputStream *ost, AVFormatContext *oc,
                       const AVCodec **codec,
                       enum AVCodecID codec_id);


  


  I'm thinking that the example sets the codec at avformat_alloc_output_context2(&enc_inf.oc, NULL, NULL, filename) but I'm not quite sure how to set it to h264.

  


  I've tried something like this avformat_alloc_output_context2(&enc_inf.oc, enc_inf.fmt, "h264", filename)

  


  But it just gives a seg fault. What am I supposed to do ?

  


  Edit : I've tried adding these two lines to video_encoder::video_encoder by deleting avformat_alloc_output_context2(&enc_inf.oc, NULL, NULL, filename); :

  


  
    video_codec = avcodec_find_encoder(AV_CODEC_ID_H264);
    enc_inf.video_st.enc = avcodec_alloc_context3(video_codec);



  


  But it resulted in these errors :
It says this every frame (A bunch of times)

  


  [mpeg @ 0x56057c465480] buffer underflow st=0 bufi=26822 size=31816


  


  Says this once when the frame encoding loop is over :

  


  [mpeg @ 0x5565ac4a04c0] start time for stream 0 is not set in estimate_timings_from_pts
[mpeg @ 0x5565ac4a04c0] stream 0 : no TS found at start of file, duration not set
[mpeg @ 0x5565ac4a04c0] Could not find codec parameters for stream 0 (Video: mpeg2video, none): unspecified size
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options