From 5e14319a111a19eec5d92de92e2dedc8b05feb55 Mon Sep 17 00:00:00 2001
From: Adrien Destugues <pulkomandy@pulkomandy.tk>
Date: Sun, 4 Nov 2018 09:36:02 +0100
Subject: [PATCH] ffmpeg: use new producer/consumer API for video decoding

This API allows us to send whole packets no matter how the video is
formatted, and get frames out as they are ready (sometimes multiple
frames per packets, which did not work well with the previous API).

Change-Id: I0bd7d4706e330bb11d87cb41e93cfc6995b4b3a5
Reviewed-on: https://review.haiku-os.org/665
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
---
 .../media/plugins/ffmpeg/AVCodecDecoder.cpp   | 121 +++++++++---------
 1 file changed, 60 insertions(+), 61 deletions(-)

diff --git a/src/add-ons/media/plugins/ffmpeg/AVCodecDecoder.cpp b/src/add-ons/media/plugins/ffmpeg/AVCodecDecoder.cpp
index aa462137f8..23fb6af38c 100644
--- a/src/add-ons/media/plugins/ffmpeg/AVCodecDecoder.cpp
+++ b/src/add-ons/media/plugins/ffmpeg/AVCodecDecoder.cpp
@@ -1239,76 +1239,75 @@ AVCodecDecoder::_UpdateMediaHeaderForAudioFrame()
 status_t
 AVCodecDecoder::_DecodeNextVideoFrame()
 {
-	while (true) {
-		status_t loadingChunkStatus
-			= _LoadNextChunkIfNeededAndAssignStartTime();
-		if (loadingChunkStatus == B_LAST_BUFFER_ERROR)
-			return _FlushOneVideoFrameFromDecoderBuffer();
-		if (loadingChunkStatus != B_OK) {
-			TRACE("AVCodecDecoder::_DecodeNextVideoFrame(): error from "
-				"GetNextChunk(): %s\n", strerror(loadingChunkStatus));
-			return loadingChunkStatus;
-		}
+	int error;
+	int send_error;
 
 #if DO_PROFILING
-		bigtime_t startTime = system_time();
+	bigtime_t startTime = system_time();
 #endif
 
-		// NOTE: In the FFMPEG 0.10.2 code example decoding_encoding.c, the
-		// length returned by avcodec_decode_video2() is used to update the
-		// packet buffer size (here it is fTempPacket.size). This way the
-		// packet buffer is allowed to contain incomplete frames so we are
-		// required to buffer the packets between different calls to
-		// _DecodeNextVideoFrame().
-		int gotVideoFrame = 0;
-		int encodedDataSizeInBytes = avcodec_decode_video2(fCodecContext,
-			fRawDecodedPicture, &gotVideoFrame, &fTempPacket);
-		if (encodedDataSizeInBytes < 0) {
-			TRACE("[v] AVCodecDecoder: ignoring error in decoding frame %lld:"
-				" %d\n", fFrame, encodedDataSizeInBytes);
-			// NOTE: An error from avcodec_decode_video2() is ignored by the
-			// FFMPEG 0.10.2 example decoding_encoding.c. Only the packet
-			// buffers are flushed accordingly
+	error = avcodec_receive_frame(fCodecContext, fRawDecodedPicture);
+
+	if (error == AVERROR(EAGAIN)) {
+		do {
+			status_t loadingChunkStatus
+				= _LoadNextChunkIfNeededAndAssignStartTime();
+			if (loadingChunkStatus == B_LAST_BUFFER_ERROR)
+				return _FlushOneVideoFrameFromDecoderBuffer();
+			if (loadingChunkStatus != B_OK) {
+				TRACE("[v] AVCodecDecoder::_DecodeNextVideoFrame(): error from "
+					"GetNextChunk(): %s\n", strerror(loadingChunkStatus));
+				return loadingChunkStatus;
+			}
+
+			char timestamp[AV_TS_MAX_STRING_SIZE];
+			av_ts_make_time_string(timestamp,
+				fTempPacket.dts, &fCodecContext->time_base);
+			TRACE("[v] Feed %d more bytes (dts %s)\n", fTempPacket.size,
+				timestamp);
+
+			send_error = avcodec_send_packet(fCodecContext, &fTempPacket);
+			if (send_error < 0 && send_error != AVERROR(EAGAIN)) {
+				TRACE("[v] AVCodecDecoder: ignoring error in decoding frame "
+				"%lld: %d\n", fFrame, error);
+			}
+
+			// Packet is consumed, clear it
 			fTempPacket.data = NULL;
 			fTempPacket.size = 0;
-			continue;
-		}
 
-		fTempPacket.size -= encodedDataSizeInBytes;
-		fTempPacket.data += encodedDataSizeInBytes;
+			error = avcodec_receive_frame(fCodecContext, fRawDecodedPicture);
+			if (error != 0 && error != AVERROR(EAGAIN)) {
+				TRACE("[v] frame %lld - decoding error, error code: %d, "
+					"chunk size: %ld\n", fFrame, error, fChunkBufferSize);
+			}
 
-		bool gotNoVideoFrame = gotVideoFrame == 0;
-		if (gotNoVideoFrame) {
-			TRACE("frame %lld - no picture yet, encodedDataSizeInBytes: %d, "
-				"chunk size: %ld\n", fFrame, encodedDataSizeInBytes,
-				fChunkBufferSize);
-			continue;
-		}
-
-#if DO_PROFILING
-		bigtime_t formatConversionStart = system_time();
-#endif
-
-		status_t handleStatus = _HandleNewVideoFrameAndUpdateSystemState();
-		if (handleStatus != B_OK)
-			return handleStatus;
-
-#if DO_PROFILING
-		bigtime_t doneTime = system_time();
-		decodingTime += formatConversionStart - startTime;
-		conversionTime += doneTime - formatConversionStart;
-		profileCounter++;
-		if (!(fFrame % 5)) {
-			printf("[v] profile: d1 = %lld, d2 = %lld (%lld) required %Ld\n",
-				decodingTime / profileCounter, conversionTime / profileCounter,
-				fFrame, bigtime_t(1000000LL / fOutputFrameRate));
-			decodingTime = 0;
-			conversionTime = 0;
-			profileCounter = 0;
-		}
-#endif
-		return B_OK;
+		} while (error != 0);
 	}
+
+#if DO_PROFILING
+	bigtime_t formatConversionStart = system_time();
+#endif
+
+	status_t handleStatus = _HandleNewVideoFrameAndUpdateSystemState();
+	if (handleStatus != B_OK)
+		return handleStatus;
+
+#if DO_PROFILING
+	bigtime_t doneTime = system_time();
+	decodingTime += formatConversionStart - startTime;
+	conversionTime += doneTime - formatConversionStart;
+	profileCounter++;
+	if (!(fFrame % 5)) {
+		printf("[v] profile: d1 = %lld, d2 = %lld (%lld) required %Ld\n",
+			decodingTime / profileCounter, conversionTime / profileCounter,
+			fFrame, bigtime_t(1000000LL / fOutputFrameRate));
+		decodingTime = 0;
+		conversionTime = 0;
+		profileCounter = 0;
+	}
+#endif
+	return error;
 }