//
// mpeg4-part2 in mipsel receivers
// http://forums.openpli.org/topic/39326-gstreamer10-and-mpeg4-part2/?hl=%2Bmpeg4+%2Bpart2
//
#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(59, 0, 100)
#include <libavcodec/bsf.h>
#endif

// mpeg4_unpack_bframes
typedef struct
{
	const AVBitStreamFilter *bsf;
	AVBSFContext *ctx;
} Mpeg4P2Context;

static Mpeg4P2Context *mpeg4p2_context_open()
{
	Mpeg4P2Context *context = NULL;
	const AVBitStreamFilter *bsf = av_bsf_get_by_name("mpeg4_unpack_bframes");
	if (bsf)
	{
		context = malloc(sizeof(Mpeg4P2Context));
		if (context)
		{
			memset(context, 0x00, sizeof(Mpeg4P2Context));
			context->bsf = bsf;
		}
	}
	return context;
}

static void mpeg4p2_write(Context_t *ctx, Mpeg4P2Context *mpeg4p2_ctx, Track_t *track, int64_t start_time, int64_t *currentVideoPts, int64_t *latest_Pts, AVPacket *pkt)
{
	*currentVideoPts = track->pts = doCalcPts(start_time, mpeg4p2_ctx->ctx->time_base_out, pkt->pts);
	if ((*currentVideoPts > *latest_Pts) && (*currentVideoPts != INVALID_PTS_VALUE))
	{
		*latest_Pts = *currentVideoPts;
	}

	track->dts = doCalcPts(start_time, mpeg4p2_ctx->ctx->time_base_out, pkt->dts);

	AudioVideoOut_t avOut;
	avOut.data       = pkt->data;
	avOut.len        = pkt->size;
	avOut.pts        = track->pts;
	avOut.dts        = track->dts;
	avOut.extradata  = mpeg4p2_ctx->ctx->par_out->extradata;
	avOut.extralen   = mpeg4p2_ctx->ctx->par_out->extradata_size;
	avOut.frameRate  = track->frame_rate;
	avOut.timeScale  = track->TimeScale;
	avOut.width      = track->width;
	avOut.height     = track->height;
	avOut.type       = "video";

	if (Write(ctx->output->video->Write, ctx, &avOut, avOut.pts) < 0)
	{
		ffmpeg_err("writing data to video device failed\n");
	}
}

static int mpeg4p2_context_reset(Mpeg4P2Context *context)
{
	int ret = 0;
	if (context && context->ctx)
	{
		// Flush
		ret = av_bsf_send_packet(context->ctx, NULL);
		if (ret == 0)
		{
			AVPacket *pkt = NULL;
			while ((ret = av_bsf_receive_packet(context->ctx, pkt)) == 0)
			{
				wrapped_frame_unref(pkt);
			}
		}
		av_bsf_free(&context->ctx);
	}

	return ret;
}

static int mpeg4p2_write_packet(Context_t *ctx, Mpeg4P2Context *mpeg4p2_ctx, Track_t *track, int cAVIdx, int64_t *pts_current, int64_t *pts_latest, AVPacket *pkt)
{
	int ret = 0;
	if (mpeg4p2_ctx)
	{
		// Setup is needed
		if (!mpeg4p2_ctx->ctx)
		{
			ret = av_bsf_alloc(mpeg4p2_ctx->bsf, &mpeg4p2_ctx->ctx);
			if (ret == 0)
			{
				AVStream *in = track->stream;
				ret = avcodec_parameters_copy(mpeg4p2_ctx->ctx->par_in, in->codecpar);
				if (ret == 0)
				{
					mpeg4p2_ctx->ctx->time_base_in = in->time_base;
					ret = av_bsf_init(mpeg4p2_ctx->ctx);
				}
			}
		}

		if (ret == 0)
		{
			ret = av_bsf_send_packet(mpeg4p2_ctx->ctx, pkt);
			if (ret == 0)
			{
				while ((ret = av_bsf_receive_packet(mpeg4p2_ctx->ctx, pkt)) == 0)
				{
					mpeg4p2_write(ctx, mpeg4p2_ctx, track, avContextTab[cAVIdx]->start_time, pts_current, pts_latest, pkt);
				}

				if (ret == AVERROR(EAGAIN))
				{
					return 0;
				}

				if (ret < 0)
				{
					ffmpeg_err("av_bsf_receive_packet failed error 0x%x\n", ret);
					mpeg4p2_context_reset(mpeg4p2_ctx);
				}
			}
		}
		else
		{
			ffmpeg_err("bsf setup failed error 0x%x\n", ret);
		}

	}
	else
	{
		ret = -1;
	}
	return ret;
}

static void mpeg4p2_context_close(Mpeg4P2Context *context)
{
	if (context)
	{
		mpeg4p2_context_reset(context);
		free(context);
		return;
	}
}