diff options
Diffstat (limited to 'media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp')
| -rw-r--r-- | media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp b/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp new file mode 100644 index 0000000..75ab514 --- /dev/null +++ b/media/libstagefright/codecs/avc/enc/src/bitstream_io.cpp @@ -0,0 +1,336 @@ +/* ------------------------------------------------------------------ + * Copyright (C) 1998-2009 PacketVideo + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either + * express or implied. + * See the License for the specific language governing permissions + * and limitations under the License. + * ------------------------------------------------------------------- + */ +#include "avcenc_lib.h" + +#define WORD_SIZE 32 + +/* array for trailing bit pattern as function of number of bits */ +/* the first one is unused. */ +const static uint8 trailing_bits[9] = {0, 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80}; + +/* ======================================================================== */ +/* Function : BitstreamInit() */ +/* Date : 11/4/2003 */ +/* Purpose : Populate bitstream structure with bitstream buffer and size */ +/* it also initializes internal data */ +/* In/out : */ +/* Return : AVCENC_SUCCESS if successed, AVCENC_FAIL if failed. */ +/* Modified : */ +/* ======================================================================== */ +/* |--------|--------|----~~~~~-----|---------|---------|---------| + ^ ^write_pos ^buf_size + bitstreamBuffer <---------> + current_word + + |-----xxxxxxxxxxxxx| = current_word 32 or 16 bits + <----> + bit_left + ======================================================================== */ + +AVCEnc_Status BitstreamEncInit(AVCEncBitstream *stream, uint8 *buffer, int buf_size, + uint8 *overrunBuffer, int oBSize) +{ + if (stream == NULL || buffer == NULL || buf_size <= 0) + { + return AVCENC_BITSTREAM_INIT_FAIL; + } + + stream->bitstreamBuffer = buffer; + + stream->buf_size = buf_size; + + stream->write_pos = 0; + + stream->count_zeros = 0; + + stream->current_word = 0; + + stream->bit_left = WORD_SIZE; + + stream->overrunBuffer = overrunBuffer; + + stream->oBSize = oBSize; + + return AVCENC_SUCCESS; +} + +/* ======================================================================== */ +/* Function : AVCBitstreamSaveWord() */ +/* Date : 3/29/2004 */ +/* Purpose : Save the current_word into the buffer, byte-swap, and */ +/* add emulation prevention insertion. */ +/* In/out : */ +/* Return : AVCENC_SUCCESS if successed, AVCENC_WRITE_FAIL if buffer is */ +/* full. */ +/* Modified : */ +/* ======================================================================== */ +AVCEnc_Status AVCBitstreamSaveWord(AVCEncBitstream *stream) +{ + int num_bits; + uint8 *write_pnt, byte; + uint current_word; + + /* check number of bytes in current_word, must always be byte-aligned!!!! */ + num_bits = WORD_SIZE - stream->bit_left; /* must be multiple of 8 !!*/ + + if (stream->buf_size - stream->write_pos <= (num_bits >> 3) + 2) /* 2 more bytes for possible EPBS */ + { + if (AVCENC_SUCCESS != AVCBitstreamUseOverrunBuffer(stream, (num_bits >> 3) + 2)) + { + return AVCENC_BITSTREAM_BUFFER_FULL; + } + } + + /* write word, byte-by-byte */ + write_pnt = stream->bitstreamBuffer + stream->write_pos; + current_word = stream->current_word; + while (num_bits) /* no need to check stream->buf_size and stream->write_pos, taken care already */ + { + num_bits -= 8; + byte = (current_word >> num_bits) & 0xFF; + if (byte != 0) + { + *write_pnt++ = byte; + stream->write_pos++; + stream->count_zeros = 0; + } + else + { + stream->count_zeros++; + *write_pnt++ = byte; + stream->write_pos++; + if (stream->count_zeros == 2) + { /* for num_bits = 32, this can add 2 more bytes extra for EPBS */ + *write_pnt++ = 0x3; + stream->write_pos++; + stream->count_zeros = 0; + } + } + } + + /* reset current_word and bit_left */ + stream->current_word = 0; + stream->bit_left = WORD_SIZE; + + return AVCENC_SUCCESS; +} + +/* ======================================================================== */ +/* Function : BitstreamWriteBits() */ +/* Date : 3/29/2004 */ +/* Purpose : Write up to machine word. */ +/* In/out : Unused bits in 'code' must be all zeros. */ +/* Return : AVCENC_SUCCESS if successed, AVCENC_WRITE_FAIL if buffer is */ +/* full. */ +/* Modified : */ +/* ======================================================================== */ +AVCEnc_Status BitstreamWriteBits(AVCEncBitstream *stream, int nBits, uint code) +{ + AVCEnc_Status status = AVCENC_SUCCESS; + int bit_left = stream->bit_left; + uint current_word = stream->current_word; + + //DEBUG_LOG(userData,AVC_LOGTYPE_INFO,"BitstreamWriteBits",nBits,-1); + + if (nBits > WORD_SIZE) /* has to be taken care of specially */ + { + return AVCENC_FAIL; /* for now */ + /* otherwise, break it down to 2 write of less than 16 bits at a time. */ + } + + if (nBits <= bit_left) /* more bits left in current_word */ + { + stream->current_word = (current_word << nBits) | code; + stream->bit_left -= nBits; + if (stream->bit_left == 0) /* prepare for the next word */ + { + status = AVCBitstreamSaveWord(stream); + return status; + } + } + else + { + stream->current_word = (current_word << bit_left) | (code >> (nBits - bit_left)); + + nBits -= bit_left; + + stream->bit_left = 0; + + status = AVCBitstreamSaveWord(stream); /* save current word */ + + stream->bit_left = WORD_SIZE - nBits; + + stream->current_word = code; /* no extra masking for code, must be handled before saving */ + } + + return status; +} + + +/* ======================================================================== */ +/* Function : BitstreamWrite1Bit() */ +/* Date : 3/30/2004 */ +/* Purpose : Write 1 bit */ +/* In/out : Unused bits in 'code' must be all zeros. */ +/* Return : AVCENC_SUCCESS if successed, AVCENC_WRITE_FAIL if buffer is */ +/* full. */ +/* Modified : */ +/* ======================================================================== */ +AVCEnc_Status BitstreamWrite1Bit(AVCEncBitstream *stream, uint code) +{ + AVCEnc_Status status; + uint current_word = stream->current_word; + + //DEBUG_LOG(userData,AVC_LOGTYPE_INFO,"BitstreamWrite1Bit",code,-1); + + //if(1 <= bit_left) /* more bits left in current_word */ + /* we can assume that there always be positive bit_left in the current word */ + stream->current_word = (current_word << 1) | code; + stream->bit_left--; + if (stream->bit_left == 0) /* prepare for the next word */ + { + status = AVCBitstreamSaveWord(stream); + return status; + } + + return AVCENC_SUCCESS; +} + + +/* ======================================================================== */ +/* Function : BitstreamTrailingBits() */ +/* Date : 3/31/2004 */ +/* Purpose : Add trailing bits and report the final EBSP size. */ +/* In/out : */ +/* Return : AVCENC_SUCCESS if successed, AVCENC_WRITE_FAIL if buffer is */ +/* full. */ +/* Modified : */ +/* ======================================================================== */ +AVCEnc_Status BitstreamTrailingBits(AVCEncBitstream *bitstream, uint *nal_size) +{ + (void)(nal_size); + + AVCEnc_Status status; + int bit_left = bitstream->bit_left; + + bit_left &= 0x7; /* modulo by 8 */ + if (bit_left == 0) bit_left = 8; + /* bitstream->bit_left == 0 cannot happen here since it would have been Saved already */ + + status = BitstreamWriteBits(bitstream, bit_left, trailing_bits[bit_left]); + + if (status != AVCENC_SUCCESS) + { + return status; + } + + /* if it's not saved, save it. */ + //if(bitstream->bit_left<(WORD_SIZE<<3)) /* in fact, no need to check */ + { + status = AVCBitstreamSaveWord(bitstream); + } + + return status; +} + +/* check whether it's byte-aligned */ +bool byte_aligned(AVCEncBitstream *stream) +{ + if (stream->bit_left % 8) + return false; + else + return true; +} + + +/* determine whether overrun buffer can be used or not */ +AVCEnc_Status AVCBitstreamUseOverrunBuffer(AVCEncBitstream* stream, int numExtraBytes) +{ + AVCEncObject *encvid = (AVCEncObject*)stream->encvid; + + if (stream->overrunBuffer != NULL) // overrunBuffer is set + { + if (stream->bitstreamBuffer != stream->overrunBuffer) // not already used + { + if (stream->write_pos + numExtraBytes >= stream->oBSize) + { + stream->oBSize = stream->write_pos + numExtraBytes + 100; + stream->oBSize &= (~0x3); // make it multiple of 4 + + // allocate new overrun Buffer + if (encvid->overrunBuffer) + { + encvid->avcHandle->CBAVC_Free((uint32*)encvid->avcHandle->userData, + (int)encvid->overrunBuffer); + } + + encvid->oBSize = stream->oBSize; + encvid->overrunBuffer = (uint8*) encvid->avcHandle->CBAVC_Malloc(encvid->avcHandle->userData, + stream->oBSize, DEFAULT_ATTR); + + stream->overrunBuffer = encvid->overrunBuffer; + if (stream->overrunBuffer == NULL) + { + return AVCENC_FAIL; + } + } + + // copy everything to overrun buffer and start using it. + memcpy(stream->overrunBuffer, stream->bitstreamBuffer, stream->write_pos); + stream->bitstreamBuffer = stream->overrunBuffer; + stream->buf_size = stream->oBSize; + } + else // overrun buffer is already used + { + stream->oBSize = stream->write_pos + numExtraBytes + 100; + stream->oBSize &= (~0x3); // make it multiple of 4 + + // allocate new overrun buffer + encvid->oBSize = stream->oBSize; + encvid->overrunBuffer = (uint8*) encvid->avcHandle->CBAVC_Malloc(encvid->avcHandle->userData, + stream->oBSize, DEFAULT_ATTR); + + if (encvid->overrunBuffer == NULL) + { + return AVCENC_FAIL; + } + + + // copy from the old buffer to new buffer + memcpy(encvid->overrunBuffer, stream->overrunBuffer, stream->write_pos); + // free old buffer + encvid->avcHandle->CBAVC_Free((uint32*)encvid->avcHandle->userData, + (int)stream->overrunBuffer); + + // assign pointer to new buffer + stream->overrunBuffer = encvid->overrunBuffer; + stream->bitstreamBuffer = stream->overrunBuffer; + stream->buf_size = stream->oBSize; + } + + return AVCENC_SUCCESS; + } + else // overrunBuffer is not enable. + { + return AVCENC_FAIL; + } + +} + + + |