yo got the .GDV cutscene video format sorted!! the gif above ^^^^ taken from actual exported vidframes....
here is the main codes, for all you chip callahans following along at home, it's a long one:
-- decoding script for Normality .GDV files
if not check_bytes(0x94, 0x19, 0x11, 0x29) then
error('GDV file header not found')
end
video = {}
audio = {}
read_uint16LE()
video.frame_count = read_uint16LE()
video.frames_per_second = read_uint16LE()
do
local packed = read_uint16LE()
audio.dpcm = (bit.band(packed, 8) ~= 0)
if bit.band(packed, 4) == 0 then
audio.bytes_per_sample = 1
else
audio.bytes_per_sample = 2
end
if bit.band(packed, 2) == 0 then
audio.channels = 1 -- mono
else
audio.channels = 2 -- stereo
end
audio.present = (bit.band(packed, 1) ~= 0)
end
audio.sample_rate = read_uint16LE()
do
local packed = read_uint16LE()
local bpp_enum = bit.band(packed, 7)
if bpp_enum == 1 then
video.bits_per_pixel = 8
elseif bpp_enum == 2 then
video.bits_per_pixel = 15
elseif bpp_enum == 3 then
video.bits_per_pixel = 16
elseif bpp_enum == 4 then
video.bits_per_pixel = 24
end
end
video.max_frame_size = read_uint16LE()
video.present = (video.max_frame_size ~= 0)
read_uint16LE()
video.width = read_uint16LE()
video.height = read_uint16LE()
if video.present then
init_video(video.width, video.height, video.frames_per_second)
if video.bits_per_pixel == 8 then
read_palette()
else
error('only 8-bit video is supported')
end
end
if audio.present then
audio.chunk_size = math.ceil(
math.floor(audio.sample_rate / video.frames_per_second)
* audio.channels
* audio.bytes_per_sample)
if audio.dpcm then
audio.chunk_size = audio.chunk_size / 2
end
init_audio(audio.sample_rate, audio.bytes_per_sample, audio.channels)
end
-- bit reader utility
local queue, qsize
function init_bit_reader()
queue = read_uint32LE()
qsize = 16
end
local function read_bits(n)
local retval = bit.band(queue, bit.lshift(1, n) - 1)
queue = bit.rshift(queue, n)
qsize = qsize - n
if qsize <= 0 then
qsize = qsize + 16
queue = bit.bor(queue, bit.lshift(read_uint16LE(), qsize))
end
return retval
end
function find_color_for_invalid_offset(offset)
local result = bit.band(0xFE, bit.rshift(bit.bnot(offset), 3))
local lastbit = bit.band(0xF, offset)
if lastbit == 0 then
result = bit.band(0xFF, result + 2)
elseif lastbit <= 8 then
result = bit.band(0xFF, result + 1)
end
return result
end
-- frame decoders
frame_decoders = {}
frame_decoders[0] = function(frame)
read_palette()
end
frame_decoders[1] = function(frame)
read_palette()
video_clear(0)
end
frame_decoders[3] = function(frame)
-- do nothing!
end
local decoder_6_subdecoders = {}
decoder_6_subdecoders[0] = function()
if read_bits(1) == 0 then
write_pixel(read_uint8())
return
end
local length = 2
local count = 0
local step
repeat
count = count + 1
step = read_bits(count)
length = length + step
until step ~= bit.lshift(1, count) - 1
for i = 1, length do
write_pixel(read_uint8())
end
end
decoder_6_subdecoders[1] = function()
if read_bits(1) == 0 then
video_advance(read_bits(4) + 2)
return
end
local b = read_uint8()
if bit.band(b, 0x80) == 0 then
video_advance(b + 18)
return
end
local b2 = read_uint8()
video_advance(bit.bor(bit.lshift(bit.band(b, 0x7F), 8), b2) + 146)
end
decoder_6_subdecoders[2] = function()
local subTag = read_bits(2)
if subTag == 3 then
local b = read_uint8()
local length = 2
if bit.band(b, 0x80) == 0x80 then
length = 3
end
local offset = bit.band(b, 0x7F)
if offset == 0 then
if get_video_pos() == 0 then
repeat_pixel(0xFF, length)
else
repeat_pixel(read_pixel(-1), length)
end
return
end
offset = offset + 1
if offset > get_video_pos() then
local set_pix = find_color_for_invalid_offset(offset - get_video_pos())
repeat_pixel(set_pix, length)
return
end
copy_pixels(-offset, length)
return
end
local next_4 = read_bits(4)
local offset = bit.bor(bit.lshift(next_4, 8), read_uint8())
if subTag == 0 and offset == 0xFFF then
return 'stop' -- end of stream
end
if subTag == 0 and offset > 0xF80 then
local length
length, offset = bit.band(offset, 0xF) + 2, bit.band(bit.rshift(offset, 4), 7)
local px1 = read_pixel(-(offset + 1))
local px2 = read_pixel(-offset)
for i = 1, length do
write_pixel(px1)
write_pixel(px2)
end
return
end
local length = subTag + 3
if offset == 0xFFF then
if get_video_pos() == 0 then
repeat_pixel(0xFF, length)
else
repeat_pixel(read_pixel(-1), length)
end
return
end
offset = 4096 - offset
if offset > get_video_pos() then
local set_pix = find_color_for_invalid_offset(offset - get_video_pos())
repeat_pixel(set_pix, length)
return
end
copy_pixels(-offset, length)
end
decoder_6_subdecoders[3] = function()
local first_byte = read_uint8()
local length = bit.rshift(first_byte, 4)
if length == 15 then
length = length + read_uint8()
end
length = length + 6
local offset = bit.bor(bit.lshift(bit.band(first_byte, 0xF), 8), read_uint8())
if offset == 0xFFF then
if get_video_pos() == 0 then
repeat_pixel(0xFF, length)
else
repeat_pixel(read_pixel(-1), length)
end
return
end
offset = 4096 - offset
if offset > get_video_pos() then
local set_pix = find_color_for_invalid_offset(offset-get_video_pos())
repeat_pixel(set_pix, length)
return
end
copy_pixels(-offset, length)
end
frame_decoders[6] = function(frame)
set_video_pos(frame.offset)
init_bit_reader()
local subdecoder
repeat
subdecoder = decoder_6_subdecoders[read_bits(2)]
until subdecoder() == 'stop'
end
decoder_8_subdecoders = {}
decoder_8_subdecoders[0] = decoder_6_subdecoders[0]
decoder_8_subdecoders[1] = decoder_6_subdecoders[1]
decoder_8_subdecoders[2] = decoder_6_subdecoders[2]
decoder_8_subdecoders[3] = function()
local first_byte = read_uint8()
if bit.band(first_byte, 0xC0) == 0xC0 then
local top_4 = read_bits(4)
local next_byte = read_uint8()
length = bit.band(first_byte, 0x3F) + 8
offset = bit.bor(bit.lshift(top_4, 8), next_byte)
copy_pixels(offset + 1, length)
return
end
local length, offset
if bit.band(first_byte, 0x80) == 0 then
local bits_6_to_4 = bit.rshift(first_byte, 4)
local bits_3_to_0 = bit.band(first_byte, 0xF)
local next_byte = read_uint8()
length = bits_6_to_4 + 6
offset = bit.bor(bit.lshift(bits_3_to_0, 8), next_byte)
else
-- read bits BEFORE read byte!
local top_4 = read_bits(4)
local next_byte = read_uint8()
length = 14 + bit.band(first_byte, 0x3F)
offset = bit.bor(bit.lshift(top_4, 8), next_byte)
end
if offset == 0xFFF then
if get_video_pos() == 0 then
repeat_pixel(0xFF, length)
else
repeat_pixel(read_pixel(-1), length)
end
return
end
offset = 4096 - offset
if offset > get_video_pos() then
local set_pix = find_color_for_invalid_offset(offset-get_video_pos())
repeat_pixel(set_pix, length)
return
end
copy_pixels(-offset, length)
end
frame_decoders[8] = function(frame)
set_video_pos(frame.offset)
init_bit_reader()
local subdecoder
repeat
subdecoder = decoder_8_subdecoders[read_bits(2)]
until subdecoder() == 'stop'
end
for i = 1, video.frame_count do
if audio.present then
copy_audio_data(audio.chunk_size)
end
if video.present then
if not check_bytes(0x05, 0x13) then
error('header for video frame #' .. i .. ' not found')
end
local frame = {}
frame.size = read_uint16LE()
do
local packed = read_uint32LE()
frame.encoding = bit.band(packed, 15)
frame.offset = bit.rshift(packed, 8)
frame.half_resolution_mode = bit.band(packed, 32) == 32
frame.quarter_resolution_mode = bit.band(packed, 16) == 16
frame.show = bit.band(packed, 128) == 0
end
frame.start = get_input_stream_pos()
local decode = frame_decoders[frame.encoding]
if not decode then
error('frame #' .. i .. ' has unsupported encoding type: ' .. frame.encoding)
end
if not frame.show then
-- send the previous frame through again
output_video_frame()
end
if frame.quarter_resolution_mode then
set_resolution_mode('quarter')
elseif frame.half_resolution_mode then
set_resolution_mode('half')
else
set_resolution_mode('full')
end
decode(frame)
if frame.show then
output_video_frame()
end
set_input_stream_pos(frame.start + frame.size)
end
end
finish_audio()
...which needs the following functions to be available:
input data stream- read_uint8(): read unsigned 8-bit integer. return as a number value
- read_uint16LE(): read unsigned 16-bit integer, little endian encoded. return as a number value
- read_uint32LE(): read unsigned 32-bit integer, little endian encoded. return as a number value
- check_bytes(...): for each parameter, read a byte from the input stream. return true if every parameter is equal to the corresponding byte, otherwise return false
- get_input_stream_pos(): return the current position of the input stream
- set_input_stream_pos(pos): set the current position of the input stream
video output- init_video(width, height, frames_per_second): allocate a block of pixels width * height for video read/write operations to work on
- read_palette(): read 256 x 3-byte RGB triplets from the input stream and set them as the current palette. each RGB component is a 12-bit value (0-63)
- video_clear(v): clear the video frame, so that every pixel has the given value v
- set_resolution_mode(mode): if mode is 'half', all pixel read/write operations must operate as if the vertical resolution is halved, i.e. pixels are twice as tall. if mode is 'quarter', all pixel operations must operate as if both vertical and horizontal resolution is halved, i.e. pixels are twice as wide and twice as tall. if mode is 'full' (the default), restore normal operation.
- set_video_pos(absolute_pos): move the pixel-write position to absolute_pos. The position value is related to x/y co-ordinates as follows: (y * video.width) + x == absolute_pos
- get_video_pos(): return the current pixel-write position
- video_advance(relative_offset): move the pixel-write position ahead from its current position by relative_offset pixels.
- write_pixel(v): write a pixel at the current pixel-write position then advance the position by 1
- read_pixel(offset): read back the pixel value at offset bytes relative to the current position. do not change the current position
- repeat_pixel(v, n): write the same pixel repeatedly n times, advance the current position by n
- copy_pixels(offset, length): take a chunk of pixels from offset relative to the current position
- output_video_frame(): signal that the current video frame is complete, and the current pixel/palette data should be sent to screen/file
audio output- init_audio(sample_rate, bytes_per_sample, num_channels): set up audio output
- copy_audio_data(length): take a chunk of data from the input stream with the given length (in bytes) and send it to audio output
- finish_audio(): close/clean up the audio output system if necessary
phew.....
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Unravelling the Secrets of "Normality" (1996)