void frame_loop(demuxer &dmux)
{
AVPacket pkt;
av_init_packet(&pkt);
pkt.data = NULL;
pkt.size = 0;
int video_stream_index = dmux.get_stream_index(AVMEDIA_TYPE_VIDEO);
AVStream *video_stream = dmux.get_stream(video_stream_index);
AVCodecContext *dec_ctx = video_stream->codec;
av_log(dec_ctx, AV_LOG_DEBUG, "time_base=(%d/%d), start_time=%ld, duration=%ld\n", video_stream->time_base.num, video_stream->time_base.den, video_stream->start_time, video_stream->duration);
int64_t seconds = 0;
int64_t stream_pts = demuxer::rescale_timestamp(video_stream, seconds * AV_TIME_BASE);
converter conv(video_stream, AV_PIX_FMT_RGB24);
while (dmux.read_next_packet(&pkt, video_stream_index) >= 0) {
AVPacket tmp = pkt;
do {
if (AVFrame *frame = dmux.decode_packet(dec_ctx, &tmp)) {
if (pkt.pts >= stream_pts) {
AVFrame *dest = conv.convert_frame(frame);
write_ppm_image(seconds, dest);
seconds += 30;
av_log(dec_ctx, AV_LOG_DEBUG, "seconds=%ld\n", seconds);
stream_pts = demuxer::rescale_timestamp(video_stream, seconds * AV_TIME_BASE);
dmux.seek(video_stream_index, stream_pts);
break;
}
}
} while (tmp.size > 0);
av_free_packet(&pkt);
}
}
void write_ppm_image(int seconds, AVFrame *frame)
{
std::ostringstream filename;
filename << "img" << std::setw(3) << std::setfill('0') << seconds << ".ppm";
write_ppm_image(filename.str().c_str(), frame->width, frame->height,
reinterpret_cast<const char*>(frame->data[0]));
}
void write_image( Image_<PixelType, ResourceType>const& output_image, boost::filesystem::path const& pathname ){
// select pgm or ppm
if( pathname.extension().native() == ".ppm" ){
// write the image
write_ppm_image( output_image.getResource(), pathname );
}
else if( pathname.extension().native() == ".pgm" ){
// output must be in PixelGray_u8
write_pgm_image( output_image.getResource(), pathname );
}
else{
throw GEO::GeneralException(std::string("Unknown extension (")+pathname.extension().native()+")", std::string(__FILE__), __LINE__);
}
}
