I have an MOV file and I want to decode it and have all frames as separate images.
So I try to configure an uncompressed media type in the following way:
// configure the source reader
IMFSourceReader* m_pReader;
MFCreateSourceReaderFromURL(filePath, NULL, &m_pReader);
// get the compressed media type
IMFMediaType* pFileVideoMediaType;
m_pReader->GetCurrentMediaType(MF_SOURCE_READER_FIRST_VIDEO_STREAM, &pFileVideoMediaType);
// create new media type for uncompressed type
IMFMediaType* pTypeUncomp;
MFCreateMediaType(&pTypeUncomp);
// copy all settings from compressed to uncompressed type
pFileVideoMediaType->CopyAllItems(pTypeUncomp);
// set the uncompressed video attributes
pTypeUncomp->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_RGB8);
pTypeUncomp->SetUINT32(MF_MT_ALL_SAMPLES_INDEPENDENT, TRUE);
pTypeUncomp->SetUINT32(MF_MT_INTERLACE_MODE, MFVideoInterlace_Progressive);
// set the new uncompressed type to source reader
m_pReader->SetCurrentMediaType(MF_SOURCE_READER_FIRST_VIDEO_STREAM, 0, pTypeUncomp);
// get the full uncompressed media type
m_pReader->GetCurrentMediaType(MF_SOURCE_READER_FIRST_VIDEO_STREAM, &pTypeUncomp);
I noticed that even I explicitly set the MF_MT_INTERLACE_MODE
to MFVideoInterlace_Progressive
the final configuration is still configured with the old mode MFVideoInterlace_MixedInterlaceOrProgressive
.
Afterwards, I loop through all samples and look at their size:
IMFSample* videoSample = nullptr;
IMFMediaBuffer* mbuffer = nullptr;
LONGLONG llTimeStamp;
DWORD streamIndex, flags;
m_pReader->ReadSample(
MF_SOURCE_READER_FIRST_VIDEO_STREAM,
0, // Flags.
&streamIndex, // Receives the actual stream index.
&flags, // Receives status flags.
&llTimeStamp, // Receives the time stamp.
&videoSample) // Receives the sample or NULL.
videoSample->ConvertToContiguousBuffer(&mbuffer);
BYTE* videoData = nullptr;
DWORD sampleBufferLength = 0;
mbuffer->Lock(&videoData, nullptr, &sampleBufferLength);
cout << sampleBufferLength << endl;
And I get quite different sizes for the samples: from 31bytes to 18000bytes.
Even changing the format to MFVideoFormat_RGB32
does not change affect the sample sizes.
This question seems to have the same issue but the solution is not fixing it.
Any help on why I can't change the interlacing and how to properly decode video frames and get image data out of samples?
Many thanks in advance.
In order to make SourceReader convert the samples to RGB you need to create it like this:
IMFAttributes* pAttr = NULL;
MFCreateAttributes(&pAttr, 1);
pAttr->SetUINT32(MF_READWRITE_ENABLE_HARDWARE_TRANSFORMS, TRUE);
pAttr->SetUINT32(MF_SOURCE_READER_ENABLE_VIDEO_PROCESSING, TRUE);
IMFSourceReader* m_pReader;
throwIfFailed(MFCreateSourceReaderFromURL(filePath, pAttr, &m_pReader), Can't create source reader from url");
pAttr->Release();
Later, you shouldn't break from the cycle when MF_SOURCE_READERF_CURRENTMEDIATYPECHANGED occurs. Now you'll have all samples with the same size. Otherwise you can use MFVideoFormat_NV12 subtype and then you won't need to specify MF_SOURCE_READER_ENABLE_VIDEO_PROCESSING attribute when creating the reader.