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Bug 1038046 - [RTSP] RTSP cannot play some H263 video streaming. r=sworkman

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This commit is contained in:
Ethan Tseng 2014-07-30 22:59:08 +08:00
parent bc4b4a91b8
commit 2df91871a8
1 changed files with 59 additions and 6 deletions
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65
netwerk/protocol/rtsp/rtsp/AH263Assembler.cpp
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@ -17,6 +17,7 @@
#include "AH263Assembler.h"
#include "ARTPSource.h"
#include "RtspPrlog.h"
#include <media/stagefright/foundation/ABuffer.h>
#include <media/stagefright/foundation/ADebug.h>
@ -99,18 +100,70 @@ ARTPAssembler::AssemblyStatus AH263Assembler::addPacket(
return MALFORMED_PACKET;
}
// RFC 4629, Sec. 5.1 General H.263+ Payload Header.
// The H.263+ payload header is structured as follows:
// 0 1
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | RR |P|V| PLEN |PEBIT|
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
//
// RR: 5 bits
// Reserved bits. It SHALL be zero and MUST be ignored by receivers.
// P: 1 bit
// Indicates the picture start or a picture segment (GOB/Slice) start or
// a video sequence end (EOS or EOSBS). Two bytes of zero bits then have
// to be prefixed to the payload of such a packet to compose a complete
// picture/GOB/slice/EOS/EOSBS start code. This bit allows the omission
// of the two first bytes of the start code, thus improving the
// compression ratio.
// V: 1 bit
// Indicates the presence of an 8-bit field containing information for
// Video Redundancy Coding (VRC), which follows immediately after the
// initial 16 bits of the payload header.
// PLEN: 6 bits
// Length, in bytes, of the extra picture header. If no extra picture
// header is attached, PLEN is 0. If PLEN>0, the extra picture header is
// attached immediately following the rest of the payload header. Note
// that the length reflects the omission of the first two bytes of the
// picture start code (PSC).
// PEBIT: 3 bits
// Indicates the number of bits that shall be ignored in the last byte
// of the picture header. If PLEN is not zero, the ignored bits shall be
// the least significant bits of the byte. If PLEN is zero, then PEBIT
// shall also be zero.
unsigned payloadHeader = U16_AT(buffer->data());
CHECK_EQ(payloadHeader >> 11, 0u); // RR=0
unsigned P = (payloadHeader >> 10) & 1;
CHECK_EQ((payloadHeader >> 9) & 1, 0u); // V=0
CHECK_EQ((payloadHeader >> 3) & 0x3f, 0u); // PLEN=0
CHECK_EQ(payloadHeader & 7, 0u); // PEBIT=0
unsigned V = (payloadHeader >> 9) & 1;
unsigned PLEN = (payloadHeader >> 3) & 0x3f;
unsigned PEBIT = payloadHeader & 7;
// V = 0
// We do not support VRC header extension for now, so just discard it if
// present.
if (V != 0u) {
queue->erase(queue->begin());
++mNextExpectedSeqNo;
LOGW("Packet discarded due to VRC (V != 0)");
return MALFORMED_PACKET;
}
// If PLEN is zero, then PEBIT shall also be zero.
if (PLEN == 0u && PEBIT != 0u) {
queue->erase(queue->begin());
++mNextExpectedSeqNo;
LOGW("Packet discarded (PEBIT != 0)");
return MALFORMED_PACKET;
}
size_t skip = PLEN + (P ? 0: 2);
buffer->setRange(buffer->offset() + skip, buffer->size() - skip);
if (P) {
buffer->data()[0] = 0x00;
buffer->data()[1] = 0x00;
} else {
buffer->setRange(buffer->offset() + 2, buffer->size() - 2);
}
mPackets.push_back(buffer);