/*
 * Copyright 2009-2010, Stephan Amßus <superstippi@gmx.de>
 * Copyright 2018, Dario Casalinuovo
 * All rights reserved. Distributed under the terms of the MIT license.
 */


#include "AVCodecEncoder.h"

#include <new>

#include <stdio.h>
#include <string.h>

#include <Application.h>
#include <Roster.h>

extern "C" {
	#include "rational.h"
}

#include "EncoderTable.h"
#include "gfx_util.h"


#undef TRACE
//#define TRACE_AV_CODEC_ENCODER
#ifdef TRACE_AV_CODEC_ENCODER
#	define TRACE	printf
#	define TRACE_IO(a...)
#else
#	define TRACE(a...)
#	define TRACE_IO(a...)
#endif


static const size_t kDefaultChunkBufferSize = 2 * 1024 * 1024;


AVCodecEncoder::AVCodecEncoder(uint32 codecID, int bitRateScale)
	:
	Encoder(),
	fBitRateScale(bitRateScale),
	fCodecID((CodecID)codecID),
	fCodec(NULL),
	fCodecContext(NULL),
	fCodecInitStatus(CODEC_INIT_NEEDED),
	fFrame(av_frame_alloc()),
	fSwsContext(NULL),
	fFramesWritten(0)
{
	TRACE("AVCodecEncoder::AVCodecEncoder()\n");
	_Init();
}


void
AVCodecEncoder::_Init()
{
	fChunkBuffer = new(std::nothrow) uint8[kDefaultChunkBufferSize];
	if (fCodecID > 0) {
		fCodec = avcodec_find_encoder(fCodecID);
		TRACE("  found AVCodec for %u: %p\n", fCodecID, fCodec);
	}

#if LIBAVCODEC_VERSION_MAJOR >= 60
	fAudioFifo = av_fifo_alloc2(0, 1, AV_FIFO_FLAG_AUTO_GROW);
#else
	fAudioFifo = av_fifo_alloc(0);
#endif

	// Initial parameters, so we know if the user changed them
	fEncodeParameters.avg_field_size = 0;
	fEncodeParameters.max_field_size = 0;
	fEncodeParameters.quality = 1.0f;
}


AVCodecEncoder::~AVCodecEncoder()
{
	TRACE("AVCodecEncoder::~AVCodecEncoder()\n");

	if (fSwsContext != NULL)
		sws_freeContext(fSwsContext);

#if LIBAVCODEC_VERSION_MAJOR >= 60
	av_fifo_freep2(&fAudioFifo);
#else
	av_fifo_free(fAudioFifo);
#endif

	if (fFrame != NULL) {
		av_frame_free(&fFrame);
	}

	if (fCodecContext != NULL) {
		avcodec_close(fCodecContext);
		avcodec_free_context(&fCodecContext);
	}

	delete[] fChunkBuffer;
}


status_t
AVCodecEncoder::AcceptedFormat(const media_format* proposedInputFormat,
	media_format* _acceptedInputFormat)
{
	TRACE("AVCodecEncoder::AcceptedFormat(%p, %p)\n", proposedInputFormat,
		_acceptedInputFormat);

	if (proposedInputFormat == NULL)
		return B_BAD_VALUE;

	if (_acceptedInputFormat != NULL) {
		*_acceptedInputFormat = *proposedInputFormat;
	}

	return B_OK;
}


status_t
AVCodecEncoder::SetUp(const media_format* inputFormat)
{
	TRACE("AVCodecEncoder::SetUp()\n");

	if (inputFormat == NULL)
		return B_BAD_VALUE;

	// Codec IDs for raw-formats may need to be figured out here.
	if (fCodec == NULL && fCodecID == AV_CODEC_ID_NONE) {
		fCodecID = raw_audio_codec_id_for(*inputFormat);
		if (fCodecID != AV_CODEC_ID_NONE)
			fCodec = avcodec_find_encoder(fCodecID);
	}
	if (fCodec == NULL) {
		TRACE("  encoder not found!\n");
		return B_NO_INIT;
	}

	fInputFormat = *inputFormat;
	fFramesWritten = 0;

	return _Setup();
}


status_t
AVCodecEncoder::GetEncodeParameters(encode_parameters* parameters) const
{
	TRACE("AVCodecEncoder::GetEncodeParameters(%p)\n", parameters);

// TODO: Implement maintaining an automatically calculated bit_rate versus
// a user specified (via SetEncodeParameters()) bit_rate. At this point, the
// fCodecContext->bit_rate may not yet have been specified (_Setup() was never
// called yet). So it cannot work like the code below, but in any case, it's
// showing how to convert between the values (albeit untested).
//	int avgBytesPerSecond = fCodecContext->bit_rate / 8;
//	int maxBytesPerSecond = (fCodecContext->bit_rate
//		+ fCodecContext->bit_rate_tolerance) / 8;
//
//	if (fInputFormat.type == B_MEDIA_RAW_AUDIO) {
//		fEncodeParameters.avg_field_size = (int32)(avgBytesPerSecond
//			/ fInputFormat.u.raw_audio.frame_rate);
//		fEncodeParameters.max_field_size = (int32)(maxBytesPerSecond
//			/ fInputFormat.u.raw_audio.frame_rate);
//	} else if (fInputFormat.type == B_MEDIA_RAW_VIDEO) {
//		fEncodeParameters.avg_field_size = (int32)(avgBytesPerSecond
//			/ fInputFormat.u.raw_video.field_rate);
//		fEncodeParameters.max_field_size = (int32)(maxBytesPerSecond
//			/ fInputFormat.u.raw_video.field_rate);
//	}

	parameters->quality = fEncodeParameters.quality;

	return B_OK;
}


status_t
AVCodecEncoder::SetEncodeParameters(encode_parameters* parameters)
{
	TRACE("AVCodecEncoder::SetEncodeParameters(%p)\n", parameters);

	if (fFramesWritten > 0)
		return B_NOT_SUPPORTED;

	fEncodeParameters.quality = parameters->quality;
	TRACE("  quality: %.5f\n", parameters->quality);
	if (fEncodeParameters.quality == 0.0f) {
		TRACE("  using default quality (1.0)\n");
		fEncodeParameters.quality = 1.0f;
	}

// TODO: Auto-bit_rate versus user supplied. See above.
//	int avgBytesPerSecond = 0;
//	int maxBytesPerSecond = 0;
//
//	if (fInputFormat.type == B_MEDIA_RAW_AUDIO) {
//		avgBytesPerSecond = (int)(parameters->avg_field_size
//			* fInputFormat.u.raw_audio.frame_rate);
//		maxBytesPerSecond = (int)(parameters->max_field_size
//			* fInputFormat.u.raw_audio.frame_rate);
//	} else if (fInputFormat.type == B_MEDIA_RAW_VIDEO) {
//		avgBytesPerSecond = (int)(parameters->avg_field_size
//			* fInputFormat.u.raw_video.field_rate);
//		maxBytesPerSecond = (int)(parameters->max_field_size
//			* fInputFormat.u.raw_video.field_rate);
//	}
//
//	if (maxBytesPerSecond < avgBytesPerSecond)
//		maxBytesPerSecond = avgBytesPerSecond;
//
//	// Reset these, so we can tell the difference between uninitialized
//	// and initialized...
//	if (avgBytesPerSecond > 0) {
//		fCodecContext->bit_rate = avgBytesPerSecond * 8;
//		fCodecContext->bit_rate_tolerance = (maxBytesPerSecond
//			- avgBytesPerSecond) * 8;
//		fBitRateControlledByUser = true;
//	}

	return _Setup();
}


status_t
AVCodecEncoder::Encode(const void* buffer, int64 frameCount,
	media_encode_info* info)
{
	TRACE("AVCodecEncoder::Encode(%p, %" B_PRId64 ", %p)\n", buffer, frameCount, info);

	if (!_OpenCodecIfNeeded())
		return B_NO_INIT;

	if (fInputFormat.type == B_MEDIA_RAW_AUDIO)
		return _EncodeAudio(buffer, frameCount, info);
	else if (fInputFormat.type == B_MEDIA_RAW_VIDEO)
		return _EncodeVideo(buffer, frameCount, info);
	else
		return B_NO_INIT;
}


// #pragma mark -


static int
get_channel_count(AVCodecContext* context)
{
#if LIBAVCODEC_VERSION_MAJOR >= 60
	return context->ch_layout.nb_channels;
#else
	return context->channels;
#endif
}


static void
set_channel_count(AVCodecContext* context, int count)
{
#if LIBAVCODEC_VERSION_MAJOR >= 60
	context->ch_layout.nb_channels = count;
#else
	context->channels = count;
#endif
}


status_t
AVCodecEncoder::_Setup()
{
	TRACE("AVCodecEncoder::_Setup\n");

	int rawBitRate;

	if (fCodecContext != NULL) {
		avcodec_close(fCodecContext);
		avcodec_free_context(&fCodecContext);
	}

	fCodecContext = avcodec_alloc_context3(fCodec);
	if (fCodecContext == NULL)
		return B_NO_INIT;

	if (fInputFormat.type == B_MEDIA_RAW_VIDEO) {
		TRACE("  B_MEDIA_RAW_VIDEO\n");

		// Check input parameters
		AVPixelFormat pixFmt = colorspace_to_pixfmt(
			fInputFormat.u.raw_video.display.format);
		if (pixFmt == AV_PIX_FMT_NONE) {
			TRACE("Invalid input colorspace\n");
			return B_BAD_DATA;
		}

		// frame rate
		fCodecContext->time_base = (AVRational){1, (int)fInputFormat.u.raw_video.field_rate};
		fCodecContext->framerate = (AVRational){(int)fInputFormat.u.raw_video.field_rate, 1};
		
		// video size
		fCodecContext->width = fInputFormat.u.raw_video.display.line_width;
		fCodecContext->height = fInputFormat.u.raw_video.display.line_count;
		fCodecContext->gop_size = 12;

		// TODO: Fix pixel format or setup conversion method...
		if (fCodec->pix_fmts != NULL) {
			for (int i = 0; fCodec->pix_fmts[i] != AV_PIX_FMT_NONE; i++) {
				// Use the last supported pixel format, which we hope is the
				// one with the best quality.
				fCodecContext->pix_fmt = fCodec->pix_fmts[i];
			}
		}

		// TODO: Setup rate control:
//		fCodecContext->rate_emu = 0;
//		fCodecContext->rc_eq = NULL;
//		fCodecContext->rc_max_rate = 0;
//		fCodecContext->rc_min_rate = 0;
		// TODO: Try to calculate a good bit rate...
		rawBitRate = (int)(fCodecContext->width * fCodecContext->height * 2
			* fInputFormat.u.raw_video.field_rate) * 8;

		// Pixel aspect ratio
		fCodecContext->sample_aspect_ratio.num
			= fInputFormat.u.raw_video.pixel_width_aspect;
		fCodecContext->sample_aspect_ratio.den
			= fInputFormat.u.raw_video.pixel_height_aspect;
		if (fCodecContext->sample_aspect_ratio.num == 0
			|| fCodecContext->sample_aspect_ratio.den == 0) {
			av_reduce(&fCodecContext->sample_aspect_ratio.num,
				&fCodecContext->sample_aspect_ratio.den, fCodecContext->width,
				fCodecContext->height, 255);
		}

		// TODO: This should already happen in AcceptFormat()
		if (fInputFormat.u.raw_video.display.bytes_per_row == 0) {
			fInputFormat.u.raw_video.display.bytes_per_row
				= fCodecContext->width * 4;
		}

		fFrame->pts = 0;

		fSwsContext = sws_getContext(fCodecContext->width,
			fCodecContext->height, pixFmt,
			fCodecContext->width, fCodecContext->height,
			fCodecContext->pix_fmt, SWS_FAST_BILINEAR, NULL, NULL, NULL);

	} else if (fInputFormat.type == B_MEDIA_RAW_AUDIO) {
		TRACE("  B_MEDIA_RAW_AUDIO\n");
		// frame rate
		fCodecContext->sample_rate = (int)fInputFormat.u.raw_audio.frame_rate;
		// channels
		set_channel_count(fCodecContext, fInputFormat.u.raw_audio.channel_count);
		// raw bitrate
		rawBitRate = fCodecContext->sample_rate * get_channel_count(fCodecContext)
			* (fInputFormat.u.raw_audio.format & media_raw_audio_format::B_AUDIO_SIZE_MASK) * 8;
		// sample format
		switch (fInputFormat.u.raw_audio.format) {
			case media_raw_audio_format::B_AUDIO_FLOAT:
				fCodecContext->sample_fmt = AV_SAMPLE_FMT_FLT;
				break;
			case media_raw_audio_format::B_AUDIO_DOUBLE:
				fCodecContext->sample_fmt = AV_SAMPLE_FMT_DBL;
				break;
			case media_raw_audio_format::B_AUDIO_INT:
				fCodecContext->sample_fmt = AV_SAMPLE_FMT_S32;
				break;
			case media_raw_audio_format::B_AUDIO_SHORT:
				fCodecContext->sample_fmt = AV_SAMPLE_FMT_S16;
				break;
			case media_raw_audio_format::B_AUDIO_UCHAR:
				fCodecContext->sample_fmt = AV_SAMPLE_FMT_U8;
				break;

			case media_raw_audio_format::B_AUDIO_CHAR:
			default:
				return B_MEDIA_BAD_FORMAT;
				break;
		}
#if LIBAVCODEC_VERSION_MAJOR >= 60
		if (fInputFormat.u.raw_audio.channel_mask == 0) {
			// guess the channel mask...
			av_channel_layout_default(&fCodecContext->ch_layout,
				fInputFormat.u.raw_audio.channel_count);
		} else {
			// The bits match 1:1 for media_multi_channels and FFmpeg defines.
			av_channel_layout_from_mask(&fCodecContext->ch_layout,
				fInputFormat.u.raw_audio.channel_mask);
		}
#else
		if (fInputFormat.u.raw_audio.channel_mask == 0) {
			// guess the channel mask...
			switch (fInputFormat.u.raw_audio.channel_count) {
				default:
				case 2:
					fCodecContext->channel_layout = AV_CH_LAYOUT_STEREO;
					break;
				case 1:
					fCodecContext->channel_layout = AV_CH_LAYOUT_MONO;
					break;
				case 3:
					fCodecContext->channel_layout = AV_CH_LAYOUT_SURROUND;
					break;
				case 4:
					fCodecContext->channel_layout = AV_CH_LAYOUT_QUAD;
					break;
				case 5:
					fCodecContext->channel_layout = AV_CH_LAYOUT_5POINT0;
					break;
				case 6:
					fCodecContext->channel_layout = AV_CH_LAYOUT_5POINT1;
					break;
				case 8:
					fCodecContext->channel_layout = AV_CH_LAYOUT_7POINT1;
					break;
				case 10:
					fCodecContext->channel_layout = AV_CH_LAYOUT_7POINT1_WIDE;
					break;
			}
		} else {
			// The bits match 1:1 for media_multi_channels and FFmpeg defines.
			fCodecContext->channel_layout = fInputFormat.u.raw_audio.channel_mask;
		}
#endif
	} else {
		TRACE("  UNSUPPORTED MEDIA TYPE!\n");
		return B_NOT_SUPPORTED;
	}

	// TODO: Support letting the user overwrite this via
	// SetEncodeParameters(). See comments there...
	int wantedBitRate = (int)(rawBitRate / fBitRateScale * fEncodeParameters.quality);
	if (wantedBitRate == 0)
		wantedBitRate = (int)(rawBitRate / fBitRateScale);

	fCodecContext->bit_rate = wantedBitRate;

	if (fInputFormat.type == B_MEDIA_RAW_AUDIO) {
		// Some audio encoders support certain bitrates only. Use the
		// closest match to the wantedBitRate.
		const int kBitRates[] = {
			32000, 40000, 48000, 56000, 64000, 80000, 96000, 112000, 128000,
			160000, 192000, 224000, 256000, 320000, 384000, 448000, 512000,
			576000, 640000
		};
		int diff = wantedBitRate;
		for (unsigned int i = 0; i < sizeof(kBitRates) / sizeof(int); i++) {
			int currentDiff = abs(wantedBitRate - kBitRates[i]);
			if (currentDiff < diff) {
				fCodecContext->bit_rate = kBitRates[i];
				diff = currentDiff;
			} else
				break;
		}
	}

	TRACE("  rawBitRate: %d, wantedBitRate: %d (%.1f), context bitrate: %" PRId64 "\n",
		rawBitRate, wantedBitRate, fEncodeParameters.quality, fCodecContext->bit_rate);

	// Add some known fixes from the FFmpeg API example:
	if (fCodecContext->codec_id == AV_CODEC_ID_MPEG2VIDEO) {
		// Just for testing, we also add B frames */
		fCodecContext->max_b_frames = 2;
	} else if (fCodecContext->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
		// Needed to avoid using macroblocks in which some coeffs overflow.
		// This does not happen with normal video, it just happens here as
		// the motion of the chroma plane does not match the luma plane.
		fCodecContext->mb_decision = 2;
	}

	// Unfortunately, we may fail later, when we try to open the codec
	// for real... but we need to delay this because we still allow
	// parameter/quality changes.
	return B_OK;
}


bool
AVCodecEncoder::_OpenCodecIfNeeded()
{
	if (fCodecInitStatus == CODEC_INIT_DONE)
		return true;

	if (fCodecInitStatus == CODEC_INIT_FAILED)
		return false;

	fCodecContext->strict_std_compliance = FF_COMPLIANCE_EXPERIMENTAL;

	// Some codecs need this to be set before open
	fFrame->format = fCodecContext->pix_fmt;
	fFrame->width = fCodecContext->width;
	fFrame->height = fCodecContext->height;
	av_frame_get_buffer(fFrame, 0);

	// Open the codec
	int result = avcodec_open2(fCodecContext, fCodec, NULL);
	if (result >= 0)
		fCodecInitStatus = CODEC_INIT_DONE;
	else
		fCodecInitStatus = CODEC_INIT_FAILED;

	TRACE("  avcodec_open(%p, %p): %d\n", fCodecContext, fCodec, result);

	return fCodecInitStatus == CODEC_INIT_DONE;

}


status_t
AVCodecEncoder::_EncodeAudio(const void* _buffer, int64 frameCount,
	media_encode_info* info)
{
	TRACE("AVCodecEncoder::_EncodeAudio(%p, %" B_PRId64 ", %p)\n", _buffer, frameCount, info);

	if (fChunkBuffer == NULL)
		return B_NO_MEMORY;

	status_t ret = B_OK;

	const uint8* buffer = reinterpret_cast<const uint8*>(_buffer);

	size_t inputSampleSize = fInputFormat.u.raw_audio.format
		& media_raw_audio_format::B_AUDIO_SIZE_MASK;
	size_t inputFrameSize = inputSampleSize
		* fInputFormat.u.raw_audio.channel_count;

	size_t bufferSize = frameCount * inputFrameSize;
	bufferSize = min_c(bufferSize, kDefaultChunkBufferSize);

	if (fCodecContext->frame_size > 1) {
		// Encoded audio. Things work differently from raw audio. We need
		// the fAudioFifo to pipe data.
#if LIBAVCODEC_VERSION_MAJOR >= 60
		if (av_fifo_grow2(fAudioFifo, bufferSize) < 0) {
			TRACE("  av_fifo_grow2() failed\n");
			return B_NO_MEMORY;
		}
		av_fifo_write(fAudioFifo, const_cast<uint8*>(buffer), bufferSize);
#else
		if (av_fifo_realloc2(fAudioFifo, av_fifo_size(fAudioFifo) + bufferSize) < 0) {
			TRACE("  av_fifo_realloc2() failed\n");
			return B_NO_MEMORY;
		}
		av_fifo_generic_write(fAudioFifo, const_cast<uint8*>(buffer), bufferSize, NULL);
#endif

		size_t frameBytes = fCodecContext->frame_size * inputFrameSize;
		uint8* tempBuffer = new(std::nothrow) uint8[frameBytes];
		if (tempBuffer == NULL)
			return B_NO_MEMORY;

		// Encode as many chunks as can be read from the FIFO.
#if LIBAVCODEC_VERSION_MAJOR >= 60
		while (av_fifo_can_read(fAudioFifo) >= frameBytes) {
			av_fifo_read(fAudioFifo, tempBuffer, frameBytes);
#else
		while (av_fifo_size(fAudioFifo) >= (int32)frameBytes) {
			av_fifo_generic_read(fAudioFifo, tempBuffer, frameBytes, NULL);
#endif

			ret = _EncodeAudio(tempBuffer, frameBytes, fCodecContext->frame_size,
				info);
			if (ret != B_OK)
				break;
		}

		delete[] tempBuffer;
	} else {
		// Raw audio. The number of bytes returned from avcodec_encode_audio()
		// is always the same as the number of input bytes.
		return _EncodeAudio(buffer, bufferSize, frameCount,
			info);
	}

	return ret;
}


status_t
AVCodecEncoder::_EncodeAudio(const uint8* buffer, size_t bufferSize,
	int64 frameCount, media_encode_info* info)
{
	status_t ret;

	// Encode one audio chunk/frame.
	AVPacket* packet = av_packet_alloc();
	// By leaving these NULL, we let the encoder allocate memory as it needs.
	// This way we don't risk iving a too small buffer.
	packet->data = NULL;
	packet->size = 0;

	int gotPacket = 0;

	if (buffer) {
		av_frame_unref(fFrame);
		fFrame->nb_samples = frameCount;

		int count = avcodec_fill_audio_frame(fFrame, get_channel_count(fCodecContext),
			fCodecContext->sample_fmt, (const uint8_t*)buffer, bufferSize, 1);

		if (count < 0) {
			TRACE("  avcodec_encode_audio() failed filling data: %d\n", count);
			av_packet_free(&packet);
			return B_ERROR;
		}

		/* Set the presentation time of the frame */
		fFrame->pts = (bigtime_t)(fFramesWritten * 1000000LL
			/ fInputFormat.u.raw_audio.frame_rate);
		fFramesWritten += fFrame->nb_samples;

		ret = avcodec_send_frame(fCodecContext, fFrame);
		gotPacket = avcodec_receive_packet(fCodecContext, packet) == 0;
	} else {
		// If called with NULL, ask the encoder to flush any buffers it may
		// have pending.
		ret = avcodec_receive_packet(fCodecContext, packet);
		gotPacket = (ret == 0);
	}

	if (buffer && fFrame->extended_data != fFrame->data)
		av_freep(&fFrame->extended_data);

	if (ret != 0) {
		TRACE("  avcodec_encode_audio() failed: %s\n", strerror(ret));
		av_packet_free(&packet);
		return B_ERROR;
	}

	fFramesWritten += frameCount;

	if (gotPacket) {
		// Setup media_encode_info, most important is the time stamp.
		info->start_time = packet->pts;

		if (packet->flags & AV_PKT_FLAG_KEY)
			info->flags = B_MEDIA_KEY_FRAME;
		else
			info->flags = 0;

		// We got a packet out of the encoder, write it to the output stream
		ret = WriteChunk(packet->data, packet->size, info);
		if (ret != B_OK) {
			TRACE("  error writing chunk: %s\n", strerror(ret));
			av_packet_free(&packet);
			return ret;
		}
	}

	av_packet_free(&packet);
	return B_OK;
}


status_t
AVCodecEncoder::_EncodeVideo(const void* buffer, int64 frameCount,
	media_encode_info* info)
{
	TRACE_IO("AVCodecEncoder::_EncodeVideo(%p, %lld, %p)\n", buffer, frameCount,
		info);

	if (fChunkBuffer == NULL)
		return B_NO_MEMORY;

	AVPacket* pkt = av_packet_alloc();
	while (frameCount > 0) {
		int bpr = fInputFormat.u.raw_video.display.bytes_per_row;
		size_t bufferSize = fInputFormat.u.raw_video.display.line_count * bpr;

		// Run the pixel format conversion
		const uint8_t* buf8 = (const uint8_t*)buffer;
		sws_scale(fSwsContext, &buf8, &bpr, 0,
			fInputFormat.u.raw_video.display.line_count, fFrame->data,
			fFrame->linesize);
		
		if (_EncodeVideoFrame(fFrame, pkt, info) == B_OK) {
			// Skip to the next frame (but usually, there is only one to encode
			// for video).
			frameCount--;
			fFramesWritten++;
			buffer = (const void*)((const uint8*)buffer + bufferSize);
		}
	}

	// TODO: we should pass a NULL AVFrame and enter "draining" mode, then flush buffers
	// when we have finished and there is no more data. We cannot do that here, though, since
	// 1. It's not efficient
	// 2. It's incorrect, since many codecs need the "next" frame to be able to do optimization.
	// if we drain the codec, they cannot work with the "next" frame.
	//_EncodeVideoFrame(NULL, pkt, info);
	//avcodec_flush_buffers(fCodecContext);
	av_packet_free(&pkt);
	return B_OK;
}


status_t
AVCodecEncoder::_EncodeVideoFrame(AVFrame* frame, AVPacket* pkt, media_encode_info* info)
{
	// Encode one video chunk/frame.
	int result = avcodec_send_frame(fCodecContext, frame);
	if (result < 0) {
		TRACE("  avcodec_send_frame() failed: %d\n", result);
		return B_ERROR;
	}

	// Increase the frame pts as in the ffmpeg sample code
	if (frame != NULL)
		frame->pts++;
	
	while (result == 0) {
		result = avcodec_receive_packet(fCodecContext, pkt);
		if (result == 0) {
			TRACE("  avcodec_receive_packet: received one packet\n");
			// Maybe we need to use this PTS to calculate start_time:
			if (pkt->pts != AV_NOPTS_VALUE) {
				TRACE("  codec frame PTS: %" B_PRId64 " (codec time_base: %d/%d)\n",
					pkt->pts, fCodecContext->time_base.num,
					fCodecContext->time_base.den);
			} else {
				TRACE("  codec frame PTS: N/A (codec time_base: %d/%d)\n",
					fCodecContext->time_base.num, fCodecContext->time_base.den);
			}
	
			// Setup media_encode_info, most important is the time stamp.
			info->start_time = (bigtime_t)(fFramesWritten * 1000000LL
				/ fInputFormat.u.raw_video.field_rate);
	
			info->flags = 0;
			if (pkt->flags & AV_PKT_FLAG_KEY)
				info->flags |= B_MEDIA_KEY_FRAME;
	
			// Write the chunk
			result = WriteChunk(pkt->data, pkt->size, info);
			if (result != B_OK) {
				TRACE("  error writing chunk: %s\n", strerror(result));
				break;
			}
		}	
		av_packet_unref(pkt);
	}
	if (result == AVERROR(EAGAIN))
		return B_OK;

	TRACE("   _EncodeVideoFrame(): returning...\n");
	return result;
}