Hey,
I am trying to decode an *.mpg video file into single frames and then
convert these frames to the ARGB format to pass them on to a DirectX-Shader
(to play them on an object).
Now my problem is that the decoding seems to work fine, but the conversion
to ARGB seems to really f*ck up. When outputting the frames, all I get is a
screwed up pixel mash and definitely not the video I encoded. And then it
crashes in the following memcpy function at some frame.
I am passing the converted frame to the texture like this (GetFrames()
returns a vector of previously created AVFrames, 640*360 is the texture and
video size):
*//-----------------------------------------------------------------*
/memcpy(textureDest,
_videoFrames->GetFrames()[_videoFramesPassed]->data,
4*640*360);/
*//-----------------------------------------------------------------*
The data-to-texture-to-shader-code itself works well, I tested it with some
random colors using D3DCOLOR_ARGB().
I decode the video like this:
*//-----------------------------------------------------------------*
/void
FramesCollection::DecodeVideo(const char* p_filename)
{
av_log(NULL, AV_LOG_ERROR, "%s","Starting video decoding\n");
// Get the format context...
int ret = avformat_open_input(&_videoFormatContext, p_filename, NULL,
NULL);
if (ret < 0)
{
av_log(NULL, AV_LOG_ERROR, "%s","Error opening file '%s'\n",
p_filename);
exit(-1);
}
// ... and fill it with stream info (contains number of frames, etc.)
av_find_stream_info(_videoFormatContext);
// Find the video stream
AVStream* stream;
for(int i = 0; i < (int)_videoFormatContext->nb_streams; i++)
{
if(_videoFormatContext->streams[i]->codec->codec_type ==
AVMEDIA_TYPE_VIDEO)
{
stream = _videoFormatContext->streams[i];
break;
}
}
// Use stream to set the context
_videoCodecContext = stream->codec;
// Find the codec
_videoCodec = avcodec_find_decoder(_videoCodecContext->codec_id);
if (!_videoCodec)
{
av_log(_videoCodecContext, AV_LOG_ERROR, "%s","codec not found\n");
exit(-1);
}
// Open the codec
if (avcodec_open(_videoCodecContext, _videoCodec) < 0)
{
av_log(_videoCodecContext, AV_LOG_ERROR, "%s","could not open
codec\n");
exit(-1);
}
// Read each frame into a packet
AVFrame *frame;
frame = avcodec_alloc_frame();
bool codexInitialized = false;
SwsContext *converterContext = NULL;
AVPacket packet;
av_init_packet(&packet);
while (av_read_frame(_videoFormatContext, &packet) == 0)
{
// Decode the packet to get this frame
int got_picture;
int length;
length = avcodec_decode_video2(_videoCodecContext, frame,
&got_picture,
&packet);
if (length < 0)
{
av_log(_videoCodecContext, AV_LOG_ERROR, "%s","Error
while decoding\n");
exit(-1);
}
if (got_picture)
{
// Convert the image from its native format to ARGB
(for shader)
// Create correct context
if (!codexInitialized)
{
converterContext =
sws_getContext(
_videoCodecContext->width, _videoCodecContext->height,
_videoCodecContext->pix_fmt,
_videoCodecContext->width, _videoCodecContext->height,
PIX_FMT_ARGB, SWS_BICUBIC,
NULL,
NULL, NULL );
}
// Convert frame to target format
AVFrame* dstFrame;
dstFrame = avcodec_alloc_frame();
avcodec_get_frame_defaults(dstFrame);
avpicture_alloc((AVPicture*)dstFrame, PIX_FMT_ARGB,
_videoCodecContext->width, _videoCodecContext->height);
sws_scale( converterContext,
frame->data, frame->linesize,
0, _videoCodecContext->height,
dstFrame->data,
dstFrame->linesize);
// Save the frame
_videoFrames.push_back(dstFrame);
}
} // END decoding each frame
// Clean up
av_free_packet(&packet);
av_free(frame);
if (converterContext)
sws_freeContext(converterContext);
if (_videoCodecContext)
avcodec_close(_videoCodecContext);
if (_videoFormatContext)
av_close_input_file(_videoFormatContext);
}/
*//-----------------------------------------------------------------*
While decoding, I get the following message each frame (don't mind the log
format, it's my own):
*//-----------------------------------------------------------------*
/swscaler ********************
lvl: 24
msg: No accelerated colorspace conversion found from yuv420p to argb./
*//-----------------------------------------------------------------*
I don't think this causes the erratic behaviour, though.
Any ideas? Cause I certainly don't have any. HELP :(
Also, if anyone knows a video format in which this would definitely work,
I'd be glad to hear it, since I can use any video format for this, anyway.
--
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