虽然FFmpeg本身有cuvid硬解,但是找不到什么好的资料,英伟达的SDK比较容易懂,参考FFmpeg源码,将NVIDIA VIDEO CODEC SDK的数据获取改为FFmpeg获取,弥补原生SDK不能以流作为数据源的不足。所用SDK版本为Video_Codec_SDK_7.1.9,英伟达官网可下载。
1.修改数据源
首先是FFmpeg的一些常规的初始化
bool VideoSource::init(const std::string sFileName, FrameQueue *pFrameQueue) {assert(0 != pFrameQueue);oSourceData_.hVideoParser = 0;oSourceData_.pFrameQueue = pFrameQueue;int i;AVCodec *pCodec;av_register_all();avformat_network_init();pFormatCtx = avformat_alloc_context();if (avformat_open_input(&pFormatCtx, sFileName.c_str(), NULL, NULL) != 0){printf("Couldn't open input stream.\n");return false;}if (avformat_find_stream_info(pFormatCtx, NULL)<0){printf("Couldn't find stream information.\n");return false;}videoindex = -1;for (i = 0; i<pFormatCtx->nb_streams; i++)if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO){videoindex = i;break;}if (videoindex == -1){printf("Didn't find a video stream.\n");return false;}pCodecCtx = pFormatCtx->streams[videoindex]->codec;pCodec = avcodec_find_decoder(pCodecCtx->codec_id);if (pCodec == NULL){printf("Codec not found.\n");return false;}//Output Info-----------------------------printf("--------------- File Information ----------------\n");av_dump_format(pFormatCtx, 0, sFileName.c_str(), 0);printf("-------------------------------------------------\n");memset(&g_stFormat, 0, sizeof(CUVIDEOFORMAT));switch (pCodecCtx->codec_id) {case AV_CODEC_ID_H263:g_stFormat.codec = cudaVideoCodec_MPEG4;break;case AV_CODEC_ID_H264:g_stFormat.codec = cudaVideoCodec_H264;break;case AV_CODEC_ID_HEVC:g_stFormat.codec = cudaVideoCodec_HEVC;break;case AV_CODEC_ID_MJPEG:g_stFormat.codec = cudaVideoCodec_JPEG;break;case AV_CODEC_ID_MPEG1VIDEO:g_stFormat.codec = cudaVideoCodec_MPEG1;break;case AV_CODEC_ID_MPEG2VIDEO:g_stFormat.codec = cudaVideoCodec_MPEG2;break;case AV_CODEC_ID_MPEG4:g_stFormat.codec = cudaVideoCodec_MPEG4;break;case AV_CODEC_ID_VP8:g_stFormat.codec = cudaVideoCodec_VP8;break;case AV_CODEC_ID_VP9:g_stFormat.codec = cudaVideoCodec_VP9;break;case AV_CODEC_ID_VC1:g_stFormat.codec = cudaVideoCodec_VC1;break;default:return false;}//这个地方的FFmoeg与cuvid的对应关系不是很确定,不过用这个参数似乎最靠谱switch (pCodecCtx->sw_pix_fmt){case AV_PIX_FMT_YUV420P:g_stFormat.chroma_format = cudaVideoChromaFormat_420;break;case AV_PIX_FMT_YUV422P:g_stFormat.chroma_format = cudaVideoChromaFormat_422;break;case AV_PIX_FMT_YUV444P:g_stFormat.chroma_format = cudaVideoChromaFormat_444;break;default:g_stFormat.chroma_format = cudaVideoChromaFormat_420;break;}//找了好久,总算是找到了FFmpeg中标识场格式和帧格式的标识位//场格式是隔行扫描的,需要做去隔行处理switch (pCodecCtx->field_order){case AV_FIELD_PROGRESSIVE:case AV_FIELD_UNKNOWN:g_stFormat.progressive_sequence = true;break;default:g_stFormat.progressive_sequence = false;break;}pCodecCtx->thread_safe_callbacks = 1;g_stFormat.coded_width = pCodecCtx->coded_width;g_stFormat.coded_height = pCodecCtx->coded_height;g_stFormat.display_area.right = pCodecCtx->width;g_stFormat.display_area.left = 0;g_stFormat.display_area.bottom = pCodecCtx->height;g_stFormat.display_area.top = 0;if (pCodecCtx->codec_id == AV_CODEC_ID_H264 || pCodecCtx->codec_id == AV_CODEC_ID_HEVC) {if (pCodecCtx->codec_id == AV_CODEC_ID_H264)h264bsfc = av_bitstream_filter_init("h264_mp4toannexb");elseh264bsfc = av_bitstream_filter_init("hevc_mp4toannexb");}return true; }
这里面非常重要的一段代码是
if (pCodecCtx->codec_id == AV_CODEC_ID_H264 || pCodecCtx->codec_id == AV_CODEC_ID_HEVC) {if (pCodecCtx->codec_id == AV_CODEC_ID_H264)h264bsfc = av_bitstream_filter_init("h264_mp4toannexb");elseh264bsfc = av_bitstream_filter_init("hevc_mp4toannexb"); }
网上有许多代码和伪代码都说实现了把数据源修改为FFmpeg,但我在尝试的时候发现cuvidCreateVideoParser创建的Parser的回调函数都没有调用。经过一番折腾,综合英伟达网站、stackoverflow和FFmpeg源码,才发现对H264数据要做一个处理才能把AVPacket有效的转为CUVIDSOURCEDATAPACKET。其中h264bsfc的定义为AVBitStreamFilterContext* h264bsfc = NULL;
2.AVPacket转CUVIDSOURCEDATAPACKET,并交给cuvidParseVideoData
void VideoSource::play_thread(LPVOID lpParam) {AVPacket *avpkt;avpkt = (AVPacket *)av_malloc(sizeof(AVPacket));CUVIDSOURCEDATAPACKET cupkt;int iPkt = 0;CUresult oResult;while (av_read_frame(pFormatCtx, avpkt) >= 0){if (bThreadExit){break;}bStarted = true;if (avpkt->stream_index == videoindex){cuCtxPushCurrent(g_oContext);if (avpkt && avpkt->size) {if (h264bsfc){av_bitstream_filter_filter(h264bsfc, pFormatCtx->streams[videoindex]->codec, NULL, &avpkt->data, &avpkt->size, avpkt->data, avpkt->size, 0);}cupkt.payload_size = (unsigned long)avpkt->size;cupkt.payload = (const unsigned char*)avpkt->data;if (avpkt->pts != AV_NOPTS_VALUE) {cupkt.flags = CUVID_PKT_TIMESTAMP;if (pCodecCtx->pkt_timebase.num && pCodecCtx->pkt_timebase.den){AVRational tb;tb.num = 1;tb.den = AV_TIME_BASE;cupkt.timestamp = av_rescale_q(avpkt->pts, pCodecCtx->pkt_timebase, tb);}elsecupkt.timestamp = avpkt->pts;}}else {cupkt.flags = CUVID_PKT_ENDOFSTREAM;}oResult = cuvidParseVideoData(oSourceData_.hVideoParser, &cupkt);if ((cupkt.flags & CUVID_PKT_ENDOFSTREAM) || (oResult != CUDA_SUCCESS)){break;}iPkt++;//printf("Succeed to read avpkt %d !\n", iPkt); checkCudaErrors(cuCtxPopCurrent(NULL));}av_free_packet(avpkt);}oSourceData_.pFrameQueue->endDecode();bStarted = false; }
这里FFmpeg读取数据包后,对H264和HEVC格式,有一个重要的处理,就是前面提到的,
if (h264bsfc) {av_bitstream_filter_filter(h264bsfc, pFormatCtx->streams[videoindex]->codec, NULL, &avpkt->data, &avpkt->size, avpkt->data, avpkt->size, 0); }
这个处理的含义见雷霄华的博客http://blog.csdn.net/leixiaohua1020/article/details/39767055。
这样,通过FFmpeg,CUVID就可以对流进行处理了。个人尝试过读取本地文件和rtsp流。FFmpeg读取rtsp流的方式竟然只需要把文件改为rtsp流的地址就可以,以前没做过流式的,我还以为会很复杂的。
3.一点数据
这是在GTX 1080上把解码进程(没做显示)开了20路解码得到的数据。20路1920X1080解码还能到平局37fps,这显卡也是6得不行。
工程源码:http://download.csdn.net/download/qq_33892166/9792997
源码遇到了一个问题,没找到原因。代码在GTX 1080和Tesla P4上的解码效果很好。P4由于驱动模式是TCC模式,所以只能解码,不能显示;1080上可解码,可显示。但是在我自己电脑上的GT940M上,即时是原生SDK在cuvidCreateDecoder的时候也总是报错CUDA_ERROR_NO_DEVICE。驱动似乎没问题,试了CUDA的demo,CUDA运算也是正常的,查的资料表明GT940M应该是支持CUVID的。希望知道原因的朋友能指教一二。
-----------------------------------------2017.7.7更新----------------------------------------
修改代码中的一处内存泄漏问题:
把play_thread()中的
if (avpkt && avpkt->size) { if (h264bsfc) {av_bitstream_filter_filter(h264bsfc, pFormatCtx->streams[videoindex]->codec, NULL, &avpkt->data, &avpkt->size, avpkt->data, avpkt->size, 0); }cupkt.payload_size = (unsigned long)avpkt->size; cupkt.payload = (const unsigned char*)avpkt->data;if (avpkt->pts != AV_NOPTS_VALUE) {cupkt.flags = CUVID_PKT_TIMESTAMP;if (pCodecCtx->pkt_timebase.num && pCodecCtx->pkt_timebase.den){AVRational tb;tb.num = 1;tb.den = AV_TIME_BASE;cupkt.timestamp = av_rescale_q(avpkt->pts, pCodecCtx->pkt_timebase, tb);}elsecupkt.timestamp = avpkt->pts; } } else { cupkt.flags = CUVID_PKT_ENDOFSTREAM; }oResult = cuvidParseVideoData(oSourceData_.hVideoParser, &cupkt); if ((cupkt.flags & CUVID_PKT_ENDOFSTREAM) || (oResult != CUDA_SUCCESS)){ break; } iPkt++;
为
AVPacket new_pkt = *avpkt;if (avpkt && avpkt->size) {if (h264bsfc){int a = av_bitstream_filter_filter(h264bsfc, pFormatCtx->streams[videoindex]->codec, NULL,&new_pkt.data, &new_pkt.size,avpkt->data, avpkt->size,avpkt->flags & AV_PKT_FLAG_KEY);if (a>0){if (new_pkt.data != avpkt->data)//-added this {av_free_packet(avpkt);avpkt->data = new_pkt.data;avpkt->size = new_pkt.size;}}else if (a<0){goto LOOP0;}*avpkt = new_pkt;}cupkt.payload_size = (unsigned long)avpkt->size;cupkt.payload = (const unsigned char*)avpkt->data;if (avpkt->pts != AV_NOPTS_VALUE) {cupkt.flags = CUVID_PKT_TIMESTAMP;if (pCodecCtx->pkt_timebase.num && pCodecCtx->pkt_timebase.den){AVRational tb;tb.num = 1;tb.den = AV_TIME_BASE;cupkt.timestamp = av_rescale_q(avpkt->pts, pCodecCtx->pkt_timebase, tb);}elsecupkt.timestamp = avpkt->pts;} } else {cupkt.flags = CUVID_PKT_ENDOFSTREAM; }oResult = cuvidParseVideoData(oSourceData_.hVideoParser, &cupkt); if ((cupkt.flags & CUVID_PKT_ENDOFSTREAM) || (oResult != CUDA_SUCCESS)) {break; }av_free(new_pkt.data);
这个泄漏是av_bitstream_filter_filter造成的,解决办法参考http://blog.csdn.net/lg1259156776/article/details/73283920 。
-----------------------------2017.8.30 补-----------------------------------
貌似还是有小伙伴被内存泄漏难住了,这里我给出我最新的读取数据包线程函数的完整代码,希望有所帮助
void VideoSource::play_thread(LPVOID lpParam) {AVPacket *avpkt;avpkt = (AVPacket *)av_malloc(sizeof(AVPacket));CUVIDSOURCEDATAPACKET cupkt;CUresult oResult;while (av_read_frame(pFormatCtx, avpkt) >= 0){ LOOP0:if (bThreadExit){break;}if (avpkt->stream_index == videoindex){AVPacket new_pkt = *avpkt;if (avpkt && avpkt->size) {if (h264bsfc){int a = av_bitstream_filter_filter(h264bsfc, pFormatCtx->streams[videoindex]->codec, NULL,&new_pkt.data, &new_pkt.size,avpkt->data, avpkt->size,avpkt->flags & AV_PKT_FLAG_KEY);if (a>0){if (new_pkt.data != avpkt->data)//-added this {av_free_packet(avpkt);avpkt->data = new_pkt.data;avpkt->size = new_pkt.size;}}else if (a<0){goto LOOP0;}*avpkt = new_pkt;}cupkt.payload_size = (unsigned long)avpkt->size;cupkt.payload = (const unsigned char*)avpkt->data;if (avpkt->pts != AV_NOPTS_VALUE) {cupkt.flags = CUVID_PKT_TIMESTAMP;if (pCodecCtx->pkt_timebase.num && pCodecCtx->pkt_timebase.den){AVRational tb;tb.num = 1;tb.den = AV_TIME_BASE;cupkt.timestamp = av_rescale_q(avpkt->pts, pCodecCtx->pkt_timebase, tb);}elsecupkt.timestamp = avpkt->pts;}}else {cupkt.flags = CUVID_PKT_ENDOFSTREAM;}oResult = cuvidParseVideoData(oSourceData_.hVideoParser, &cupkt);if ((cupkt.flags & CUVID_PKT_ENDOFSTREAM) || (oResult != CUDA_SUCCESS)){break;}av_free(new_pkt.data);}elseav_free_packet(avpkt);}oSourceData_.pFrameQueue->endDecode();bStarted = false;if (pCodecCtx->codec_id == AV_CODEC_ID_H264 || pCodecCtx->codec_id == AV_CODEC_ID_HEVC) {av_bitstream_filter_close(h264bsfc);} }