From Tanguy Fautre (Aris Technologies), ffmpeg plugin

src/osgPlugins/ffmpeg/FFmpegDecoderVideo.cpp

@@ -0,0 +1,310 @@
+
+#include "FFmpegDecoderVideo.hpp"
+
+#include <osg/Notify>
+
+#include <stdexcept>
+#include <string.h>
+
+
+
+namespace osgFFmpeg {
+
+
+
+FFmpegDecoderVideo::FFmpegDecoderVideo(PacketQueue & packets, FFmpegClocks & clocks) :
+    m_packets(packets),
+    m_clocks(clocks),
+    m_stream(0),
+    m_context(0),
+    m_codec(0),
+    m_packet_data(0),
+    m_bytes_remaining(0),
+    m_packet_pts(AV_NOPTS_VALUE),
+    m_user_data(0),
+    m_publish_func(0),
+    m_exit(false)
+{
+
+}
+
+
+
+FFmpegDecoderVideo::~FFmpegDecoderVideo()
+{
+    if (isRunning())
+    {
+        m_exit = true;
+        join();
+    }
+}
+
+
+
+void FFmpegDecoderVideo::open(AVStream * const stream)
+{
+    m_stream = stream;
+    m_context = stream->codec;
+
+    // Trust the video size given at this point
+    // (avcodec_open seems to sometimes return a 0x0 size)
+    m_width = m_context->width;
+    m_height = m_context->height;
+    findAspectRatio();
+
+    // Find out whether we support Alpha channel
+    m_alpha_channel = (m_context->pix_fmt == PIX_FMT_YUVA420P);
+
+    // Find out the framerate
+    m_frame_rate = av_q2d(stream->r_frame_rate);
+
+    // Find the decoder for the video stream
+    m_codec = avcodec_find_decoder(m_context->codec_id);
+
+    if (m_codec == 0)
+        throw std::runtime_error("avcodec_find_decoder() failed");
+
+    // Inform the codec that we can handle truncated bitstreams
+    //if (p_codec->capabilities & CODEC_CAP_TRUNCATED)
+    //    m_context->flags |= CODEC_FLAG_TRUNCATED;
+
+    // Open codec
+    if (avcodec_open(m_context, m_codec) < 0)
+        throw std::runtime_error("avcodec_open() failed");
+
+    // Allocate video frame
+    m_frame.reset(avcodec_alloc_frame(), av_free);
+
+    // Allocate converted RGB frame
+    m_frame_rgba.reset(avcodec_alloc_frame(), av_free);
+    m_buffer_rgba.resize(avpicture_get_size(PIX_FMT_RGB32, width(), height()));
+    m_buffer_rgba_public.resize(m_buffer_rgba.size());
+
+    // Assign appropriate parts of the buffer to image planes in m_frame_rgba
+    avpicture_fill((AVPicture *) m_frame_rgba.get(), &m_buffer_rgba[0], PIX_FMT_RGB32, width(), height());
+
+    // Override get_buffer()/release_buffer() from codec context in order to retrieve the PTS of each frame.
+    m_context->opaque = this;
+    m_context->get_buffer = getBuffer;
+    m_context->release_buffer = releaseBuffer;
+}
+
+
+
+void FFmpegDecoderVideo::run()
+{
+    try
+    {
+        decodeLoop();
+    }
+
+    catch (const std::exception & error)
+    {
+        osg::notify(osg::WARN) << "FFmpegDecoderVideo::run : " << error.what() << std::endl;
+    }
+
+    catch (...)
+    {
+        osg::notify(osg::WARN) << "FFmpegDecoderVideo::run : unhandled exception" << std::endl;
+    }
+}
+
+
+
+void FFmpegDecoderVideo::decodeLoop()
+{
+    FFmpegPacket packet;
+    double pts;
+
+    while (! m_exit)
+    {
+        // Work on the current packet until we have decoded all of it
+
+        while (m_bytes_remaining > 0)
+        {
+            // Save global PTS to be stored in m_frame via getBuffer()
+
+            m_packet_pts = packet.packet.pts;
+
+            // Decode video frame
+
+            int frame_finished = 0;
+
+            const int bytes_decoded = avcodec_decode_video(m_context, m_frame.get(), &frame_finished, m_packet_data, m_bytes_remaining);
+
+            if (bytes_decoded < 0)
+                throw std::runtime_error("avcodec_decode_video failed()");
+
+            m_bytes_remaining -= bytes_decoded;
+            m_packet_data += bytes_decoded;
+
+            // Find out the frame pts
+
+            if (packet.packet.dts == AV_NOPTS_VALUE && m_frame->opaque != 0 && *reinterpret_cast<const int64_t*>(m_frame->opaque) != AV_NOPTS_VALUE)
+            {
+                pts = *reinterpret_cast<const int64_t*>(m_frame->opaque);
+            }
+            else if (packet.packet.dts != AV_NOPTS_VALUE)
+            {
+                pts = packet.packet.dts;
+            }
+            else
+            {
+                pts = 0;
+            }
+
+            pts *= av_q2d(m_stream->time_base);
+
+            // Publish the frame if we have decoded a complete frame
+            if (frame_finished)
+            {
+                const double synched_pts = m_clocks.videoSynchClock(m_frame.get(), av_q2d(m_stream->time_base), pts);
+                const double frame_delay = m_clocks.videoRefreshSchedule(synched_pts);
+
+                publishFrame(frame_delay);
+            }
+        }
+
+        // Get the next packet
+
+        pts = 0;
+
+        if (packet.valid())
+            packet.clear();
+
+        bool is_empty = true;
+        packet = m_packets.timedPop(is_empty, 10);
+
+        if (! is_empty)
+        {
+            if (packet.type == FFmpegPacket::PACKET_DATA)
+            {
+                m_bytes_remaining = packet.packet.size;
+                m_packet_data = packet.packet.data;
+            }
+            else if (packet.type == FFmpegPacket::PACKET_FLUSH)
+            {
+                avcodec_flush_buffers(m_context);
+                m_clocks.rewindVideo();
+            }
+        }
+    }
+}
+
+
+
+void FFmpegDecoderVideo::findAspectRatio()
+{
+    double ratio = 0.0;
+
+    if (m_context->sample_aspect_ratio.num != 0)
+        ratio = (av_q2d(m_context->sample_aspect_ratio) * m_width) / m_height;
+
+    if (ratio <= 0.0)
+        ratio = double(m_width) / double(m_height);
+
+    m_aspect_ratio = ratio;
+}
+
+
+
+void FFmpegDecoderVideo::publishFrame(const double delay)
+{
+    // If no publishing function, just ignore the frame
+    if (m_publish_func == 0)
+        return;
+
+    // If the display delay is too small, we better skip the frame.
+    if (delay < -0.010)
+        return;
+
+    const AVPicture * const src = (const AVPicture *) m_frame.get();
+    AVPicture * const dst = (AVPicture *) m_frame_rgba.get();
+
+    // Convert YUVA420p (i.e. YUV420p plus alpha channel) using our own routine
+
+    if (m_context->pix_fmt == PIX_FMT_YUVA420P)
+        yuva420pToRgba(dst, src, width(), height());
+    else
+        img_convert(dst, PIX_FMT_RGB32, src, m_context->pix_fmt, width(), height());
+
+    // Flip and swap buffer
+    swapBuffers();
+
+    // Wait 'delay' seconds before publishing the picture.
+    int i_delay = static_cast<int>(delay * 1000000 + 0.5);
+
+    while (i_delay > 1000)
+    {
+        // Avoid infinite/very long loops
+        if (m_exit)
+            return;
+
+        const int micro_delay = (std::min)(1000000, i_delay);
+
+        OpenThreads::Thread::microSleep(micro_delay);
+
+        i_delay -= micro_delay;
+    }
+
+    m_publish_func(* this, m_user_data);
+}
+
+
+
+void FFmpegDecoderVideo::swapBuffers()
+{
+    for (int h = 0; h < height(); ++h)
+        memcpy(&m_buffer_rgba_public[(height() - h - 1) * width() * 4], &m_buffer_rgba[h * width() * 4], width() * 4);
+}
+
+
+
+void FFmpegDecoderVideo::yuva420pToRgba(AVPicture * const dst, const AVPicture * const src, int width, int height)
+{
+    img_convert(dst, PIX_FMT_RGB32, src, m_context->pix_fmt, width, height);
+
+    const size_t bpp = 4;
+
+    uint8_t * a_dst = dst->data[0] + 3;
+
+    for (int h = 0; h < height; ++h) {
+
+        const uint8_t * a_src = src->data[3] + h * src->linesize[3];
+
+        for (int w = 0; w < width; ++w) {
+            *a_dst = *a_src;
+            a_dst += bpp;
+            a_src += 1;
+        }
+    }
+}
+
+
+
+int FFmpegDecoderVideo::getBuffer(AVCodecContext * const context, AVFrame * const picture)
+{
+    const FFmpegDecoderVideo * const this_ = reinterpret_cast<const FFmpegDecoderVideo*>(context->opaque);
+
+    const int result = avcodec_default_get_buffer(context, picture);
+    int64_t * p_pts = reinterpret_cast<int64_t*>( av_malloc(sizeof(int64_t)) );
+
+    *p_pts = this_->m_packet_pts;
+    picture->opaque = p_pts;
+
+    return result;
+}
+
+
+
+void FFmpegDecoderVideo::releaseBuffer(AVCodecContext * const context, AVFrame * const picture)
+{
+    if (picture != 0)
+        av_freep(&picture->opaque);
+
+    avcodec_default_release_buffer(context, picture);
+}
+
+
+
+} // namespace osgFFmpeg