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Update VP8 according to RFC 7741 #513

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Update VP8 according to RFC 7741 #513

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85 changes: 74 additions & 11 deletions src/org/jitsi/impl/neomedia/codec/video/vp8/DePacketizer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -418,7 +418,7 @@ public static boolean isKeyFrame(byte[] buf, int off, int len)

/**
* A class that represents the VP8 Payload Descriptor structure defined
* in {@link "http://tools.ietf.org/html/draft-ietf-payload-vp8-10"}
* in {@link "https://tools.ietf.org/html/rfc7741"}
*/
public static class VP8PayloadDescriptor
{
Expand Down Expand Up @@ -475,22 +475,37 @@ public static class VP8PayloadDescriptor
private static final byte N_BIT = (byte) 0x20;

/**
* Gets the temporal layer index (TID), if that's set.
* The bitmask for the temporal-layer index
*/
private static final byte TID_MASK = (byte) 0xC0;

/**
* Y bit from the TID/Y/KEYIDX extension byte.
*/
private static final byte Y_BIT = (byte) 0x20;

/**
* The bitmask for the temporal key frame index
*/
private static final byte KEYIDX_MASK = (byte) 0x1F;

/**
* Gets the TID/Y/KEYIDX extension byte if available
*
* @param buf the byte buffer that holds the VP8 packet.
* @param off the offset in the byte buffer where the VP8 packet starts.
* @param len the length of the VP8 packet.
*
* @return the temporal layer index (TID), if that's set, -1 otherwise.
* @return the TID/Y/KEYIDX extension byte, if that's set, -1 otherwise.
*/
public static int getTemporalLayerIndex(byte[] buf, int off, int len)
private static byte getTidYKeyIdxExtensionByte(byte[] buf, int off, int len)
{
if (buf == null || buf.length < off + len || len < 2)
{
return -1;
}

if ((buf[off] & X_BIT) == 0 || (buf[off+1] & T_BIT) == 0)
if ((buf[off] & X_BIT) == 0 || (buf[off+1] & (T_BIT | K_BIT)) == 0)
{
return -1;
}
Expand All @@ -501,7 +516,55 @@ public static int getTemporalLayerIndex(byte[] buf, int off, int len)
return -1;
}

return (buf[off + sz - 1] & 0xc0) >> 6;
return (byte) (buf[off + sz - 1] & 0xFF);
}

/**
* Gets the temporal layer index (TID), if that's set.
*
* @param buf the byte buffer that holds the VP8 packet.
* @param off the offset in the byte buffer where the VP8 packet starts.
* @param len the length of the VP8 packet.
*
* @return the temporal layer index (TID), if that's set, -1 otherwise.
*/
public static int getTemporalLayerIndex(byte[] buf, int off, int len)
{
byte tidYKeyIdxByte = getTidYKeyIdxExtensionByte(buf, off, len);

return tidYKeyIdxByte != -1 && (buf[off+1] & T_BIT) != 0 ?(tidYKeyIdxByte & TID_MASK) >> 6 : tidYKeyIdxByte;
}

/**
* Gets the 1 layer sync bit (Y BIT), if that's set.
*
* @param buf the byte buffer that holds the VP8 packet.
* @param off the offset in the byte buffer where the VP8 packet starts.
* @param len the length of the VP8 packet.
*
* @return the 1 layer sync bit (Y BIT), if that's set, -1 otherwise.
*/
public static int getFirstLayerSyncBit(byte[] buf, int off, int len)
{
byte tidYKeyIdxByte = getTidYKeyIdxExtensionByte(buf, off, len);

return tidYKeyIdxByte != -1 ? (tidYKeyIdxByte & Y_BIT) >> 5 : tidYKeyIdxByte;
}

/**
* Gets the temporal key frame index (KEYIDX), if that's set.
*
* @param buf the byte buffer that holds the VP8 packet.
* @param off the offset in the byte buffer where the VP8 packet starts.
* @param len the length of the VP8 packet.
*
* @return the temporal key frame index (KEYIDX), if that's set, -1 otherwise.
*/
public static int getTemporalKeyFrameIndex(byte[] buf, int off, int len)
{
byte tidYKeyIdxByte = getTidYKeyIdxExtensionByte(buf, off, len);

return tidYKeyIdxByte != -1 && (buf[off+1] & K_BIT) != 0 ? (tidYKeyIdxByte & KEYIDX_MASK) : tidYKeyIdxByte;
}

/**
Expand Down Expand Up @@ -568,7 +631,7 @@ public static int getSize(byte[] input, int offset, int length)
if ((input[offset+2] & M_BIT) != 0)
size++;
}
if ((input[offset+1] & L_BIT) != 0)
if ((input[offset+1] & (L_BIT | T_BIT)) != 0)
size++;
if ((input[offset+1] & (T_BIT | K_BIT)) != 0)
size++;
Expand Down Expand Up @@ -807,14 +870,14 @@ public static String toString(byte[] buf, int off, int len)

/**
* A class that represents the VP8 Payload Header structure defined
* in {@link "http://tools.ietf.org/html/draft-ietf-payload-vp8-10"}
* in {@link "https://tools.ietf.org/html/rfc7741"}
*/
public static class VP8PayloadHeader
{
/**
* S bit of the Payload Descriptor.
* P bit of the Payload Descriptor.
*/
private static final byte S_BIT = (byte) 0x01;
private static final byte P_BIT = (byte) 0x01;

/**
* Returns true if the <tt>P</tt> (inverse key frame flag) field of the
Expand All @@ -829,7 +892,7 @@ public static boolean isKeyFrame(byte[] input, int offset)
// When set to 0 the current frame is a key frame. When set to 1
// the current frame is an interframe. Defined in [RFC6386]

return (input[offset] & S_BIT) == 0;
return (input[offset] & P_BIT) == 0;
}
}

Expand Down