X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=ffmpeg_capture.cpp;h=fb1b223c326f4e789193da4e078c65a48d729ec5;hb=96cb6414f85e0ef4d660b7bd56267303e80fcd05;hp=b5768770dae37201ba5dd7064901f6059196dfe5;hpb=0f5a145f0cd11cb043e1cefc6bf6187bdac31bbd;p=nageru

diff --git a/ffmpeg_capture.cpp b/ffmpeg_capture.cpp
index b576877..fb1b223 100644
--- a/ffmpeg_capture.cpp
+++ b/ffmpeg_capture.cpp
@@ -200,7 +200,7 @@ YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *f
 }  // namespace
 
 FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
-	: filename(filename), width(width), height(height)
+	: filename(filename), width(width), height(height), video_timebase{1, 1}
 {
 	// Not really used for anything.
 	description = "Video: " + filename;
@@ -351,7 +351,7 @@ bool FFmpegCapture::play_video(const string &pathname)
 	}
 
 	const AVCodecParameters *codecpar = format_ctx->streams[video_stream_index]->codecpar;
-	AVRational video_timebase = format_ctx->streams[video_stream_index]->time_base;
+	video_timebase = format_ctx->streams[video_stream_index]->time_base;
 	AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 	if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 		fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
@@ -371,51 +371,18 @@ bool FFmpegCapture::play_video(const string &pathname)
 
 	internal_rewind();
 
-	unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(nullptr, sws_freeContext);
-	int sws_last_width = -1, sws_last_height = -1, sws_last_src_format = -1;
-	AVPixelFormat sws_dst_format = AVPixelFormat(-1);  // In practice, always initialized.
-
 	// Main loop.
 	while (!producer_thread_should_quit.should_quit()) {
-		if (process_queued_commands(format_ctx.get(), pathname, last_modified)) {
+		if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
 			return true;
 		}
 
-		// Read packets until we have a frame or there are none left.
-		int frame_finished = 0;
-		AVFrameWithDeleter frame = av_frame_alloc_unique();
-		bool eof = false;
-		do {
-			AVPacket pkt;
-			unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
-				&pkt, av_packet_unref);
-			av_init_packet(&pkt);
-			pkt.data = nullptr;
-			pkt.size = 0;
-			if (av_read_frame(format_ctx.get(), &pkt) == 0) {
-				if (pkt.stream_index != video_stream_index) {
-					// Ignore audio for now.
-					continue;
-				}
-				if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
-					fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
-					return false;
-				}
-			} else {
-				eof = true;  // Or error, but ignore that for the time being.
-			}
-
-			int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
-			if (err == 0) {
-				frame_finished = true;
-				break;
-			} else if (err != AVERROR(EAGAIN)) {
-				fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
-				return false;
-			}
-		} while (!eof);
-
-		if (!frame_finished) {
+		bool error;
+		AVFrameWithDeleter frame = decode_frame(format_ctx.get(), codec_ctx.get(), pathname, video_stream_index, &error);
+		if (error) {
+			return false;
+		}
+		if (frame == nullptr) {
 			// EOF. Loop back to the start if we can.
 			if (av_seek_frame(format_ctx.get(), /*stream_index=*/-1, /*timestamp=*/0, /*flags=*/0) < 0) {
 				fprintf(stderr, "%s: Rewind failed, not looping.\n", pathname.c_str());
@@ -432,87 +399,50 @@ bool FFmpegCapture::play_video(const string &pathname)
 			continue;
 		}
 
-		if (sws_ctx == nullptr ||
-		    sws_last_width != frame->width ||
-		    sws_last_height != frame->height ||
-		    sws_last_src_format != frame->format) {
-			sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
-			sws_ctx.reset(
-				sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
-					width, height, sws_dst_format,
-					SWS_BICUBIC, nullptr, nullptr, nullptr));
-			sws_last_width = frame->width;
-			sws_last_height = frame->height;
-			sws_last_src_format = frame->format;
-		}
-		if (sws_ctx == nullptr) {
-			fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
+		VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
+		FrameAllocator::Frame video_frame = make_video_frame(frame.get(), pathname, &error);
+		if (error) {
 			return false;
 		}
 
-		VideoFormat video_format;
-		video_format.width = width;
-		video_format.height = height;
-		if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
-			video_format.stride = width * 4;
-		} else {
-			assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
-			video_format.stride = width;
-		}
-		video_format.frame_rate_nom = video_timebase.den;
-		video_format.frame_rate_den = av_frame_get_pkt_duration(frame.get()) * video_timebase.num;
-		if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
-			// Invalid frame rate.
-			video_format.frame_rate_nom = 60;
-			video_format.frame_rate_den = 1;
-		}
-		video_format.has_signal = true;
-		video_format.is_connected = true;
-
-		next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
-		last_pts = frame->pts;
-
-		FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
-		if (video_frame.data != nullptr) {
-			uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
-			int linesizes[4] = { 0, 0, 0, 0 };
-			if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
-				pic_data[0] = video_frame.data;
-				linesizes[0] = video_format.stride;
-				video_frame.len = video_format.stride * height;
-			} else {
-				assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
-				const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
-
-				int chroma_width = AV_CEIL_RSHIFT(int(width), desc->log2_chroma_w);
-				int chroma_height = AV_CEIL_RSHIFT(int(height), desc->log2_chroma_h);
-
-				pic_data[0] = video_frame.data;
-				linesizes[0] = width;
-
-				pic_data[1] = pic_data[0] + width * height;
-				linesizes[1] = chroma_width;
-
-				pic_data[2] = pic_data[1] + chroma_width * chroma_height;
-				linesizes[2] = chroma_width;
-
-				video_frame.len = width * height + 2 * chroma_width * chroma_height;
-
-				current_frame_ycbcr_format = decode_ycbcr_format(desc, frame.get());
-			}
-			sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
-			video_frame.received_timestamp = next_frame_start;
-		}
-
 		FrameAllocator::Frame audio_frame;
 		AudioFormat audio_format;
                 audio_format.bits_per_sample = 32;
                 audio_format.num_channels = 8;
 
-		producer_thread_should_quit.sleep_until(next_frame_start);
-		frame_callback(timecode++,
-			video_frame, 0, video_format,
-			audio_frame, 0, audio_format);
+		for ( ;; ) {
+			next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
+			video_frame.received_timestamp = next_frame_start;
+			bool finished_wakeup = producer_thread_should_quit.sleep_until(next_frame_start);
+			if (finished_wakeup) {
+				frame_callback(timecode++,
+					video_frame, 0, video_format,
+					audio_frame, 0, audio_format);
+				break;
+			} else {
+				if (producer_thread_should_quit.should_quit()) break;
+
+				bool rewound = false;
+				if (process_queued_commands(format_ctx.get(), pathname, last_modified, &rewound)) {
+					return true;
+				}
+				// If we just rewound, drop this frame on the floor and be done.
+				if (rewound) {
+					video_frame_allocator->release_frame(video_frame);
+					break;
+				}
+				// OK, we didn't, so probably a rate change. Recalculate next_frame_start,
+				// but if it's now in the past, we'll reset the origin, so that we don't
+				// generate a huge backlog of frames that we need to run through quickly.
+				next_frame_start = compute_frame_start(frame->pts, pts_origin, video_timebase, start, rate);
+				steady_clock::time_point now = steady_clock::now();
+				if (next_frame_start < now) {
+					pts_origin = frame->pts;
+					start = next_frame_start = now;
+				}
+			}
+		}
+		last_pts = frame->pts;
 	}
 	return true;
 }
@@ -523,7 +453,7 @@ void FFmpegCapture::internal_rewind()
 	start = next_frame_start = steady_clock::now();
 }
 
-bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified)
+bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const std::string &pathname, timespec last_modified, bool *rewound)
 {
 	// Process any queued commands from other threads.
 	vector<QueuedCommand> commands;
@@ -545,10 +475,14 @@ bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const s
 				return true;
 			}
 			internal_rewind();
+			if (rewound != nullptr) {
+				*rewound = true;
+			}
 			break;
 
 		case QueuedCommand::CHANGE_RATE:
-			start = next_frame_start;
+			// Change the origin to the last played frame.
+			start = compute_frame_start(last_pts, pts_origin, video_timebase, start, rate);
 			pts_origin = last_pts;
 			rate = cmd.new_rate;
 			break;
@@ -556,3 +490,131 @@ bool FFmpegCapture::process_queued_commands(AVFormatContext *format_ctx, const s
 	}
 	return false;
 }
+
+AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCodecContext *codec_ctx, const std::string &pathname, int video_stream_index, bool *error)
+{
+	*error = false;
+
+	// Read packets until we have a frame or there are none left.
+	bool frame_finished = false;
+	AVFrameWithDeleter frame = av_frame_alloc_unique();
+	bool eof = false;
+	do {
+		AVPacket pkt;
+		unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
+			&pkt, av_packet_unref);
+		av_init_packet(&pkt);
+		pkt.data = nullptr;
+		pkt.size = 0;
+		if (av_read_frame(format_ctx, &pkt) == 0) {
+			if (pkt.stream_index != video_stream_index) {
+				// Ignore audio for now.
+				continue;
+			}
+			if (avcodec_send_packet(codec_ctx, &pkt) < 0) {
+				fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
+				*error = true;
+				return AVFrameWithDeleter(nullptr);
+			}
+		} else {
+			eof = true;  // Or error, but ignore that for the time being.
+		}
+
+		int err = avcodec_receive_frame(codec_ctx, frame.get());
+		if (err == 0) {
+			frame_finished = true;
+			break;
+		} else if (err != AVERROR(EAGAIN)) {
+			fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
+			*error = true;
+			return AVFrameWithDeleter(nullptr);
+		}
+	} while (!eof);
+
+	if (frame_finished)
+		return frame;
+	else
+		return AVFrameWithDeleter(nullptr);
+}
+
+VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
+{
+	VideoFormat video_format;
+	video_format.width = width;
+	video_format.height = height;
+	if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
+		video_format.stride = width * 4;
+	} else {
+		assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
+		video_format.stride = width;
+	}
+	video_format.frame_rate_nom = video_timebase.den;
+	video_format.frame_rate_den = av_frame_get_pkt_duration(frame) * video_timebase.num;
+	if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
+		// Invalid frame rate.
+		video_format.frame_rate_nom = 60;
+		video_format.frame_rate_den = 1;
+	}
+	video_format.has_signal = true;
+	video_format.is_connected = true;
+	return video_format;
+}
+
+FrameAllocator::Frame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &pathname, bool *error)
+{
+	*error = false;
+
+	FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
+	if (video_frame.data == nullptr) {
+		return video_frame;
+	}
+
+	if (sws_ctx == nullptr ||
+	    sws_last_width != frame->width ||
+	    sws_last_height != frame->height ||
+	    sws_last_src_format != frame->format) {
+		sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
+		sws_ctx.reset(
+			sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
+				width, height, sws_dst_format,
+				SWS_BICUBIC, nullptr, nullptr, nullptr));
+		sws_last_width = frame->width;
+		sws_last_height = frame->height;
+		sws_last_src_format = frame->format;
+	}
+	if (sws_ctx == nullptr) {
+		fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
+		*error = true;
+		return video_frame;
+	}
+
+	uint8_t *pic_data[4] = { nullptr, nullptr, nullptr, nullptr };
+	int linesizes[4] = { 0, 0, 0, 0 };
+	if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
+		pic_data[0] = video_frame.data;
+		linesizes[0] = width * 4;
+		video_frame.len = (width * 4) * height;
+	} else {
+		assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
+		const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
+
+		int chroma_width = AV_CEIL_RSHIFT(int(width), desc->log2_chroma_w);
+		int chroma_height = AV_CEIL_RSHIFT(int(height), desc->log2_chroma_h);
+
+		pic_data[0] = video_frame.data;
+		linesizes[0] = width;
+
+		pic_data[1] = pic_data[0] + width * height;
+		linesizes[1] = chroma_width;
+
+		pic_data[2] = pic_data[1] + chroma_width * chroma_height;
+		linesizes[2] = chroma_width;
+
+		video_frame.len = width * height + 2 * chroma_width * chroma_height;
+
+		current_frame_ycbcr_format = decode_ycbcr_format(desc, frame);
+	}
+	sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
+
+	return video_frame;
+}