# # Parse a AVI movie file produced by many digital camera # # import struct, array from random import randrange avi_verbose = 0 huffman_table = array.array('c', "\xFF\xC4\x01\xA2\x00\x00\x01\x05\x01\x01\x01\x01"\ "\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x02"\ "\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x01\x00\x03"\ "\x01\x01\x01\x01\x01\x01\x01\x01\x01\x00\x00\x00"\ "\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09"\ "\x0A\x0B\x10\x00\x02\x01\x03\x03\x02\x04\x03\x05"\ "\x05\x04\x04\x00\x00\x01\x7D\x01\x02\x03\x00\x04"\ "\x11\x05\x12\x21\x31\x41\x06\x13\x51\x61\x07\x22"\ "\x71\x14\x32\x81\x91\xA1\x08\x23\x42\xB1\xC1\x15"\ "\x52\xD1\xF0\x24\x33\x62\x72\x82\x09\x0A\x16\x17"\ "\x18\x19\x1A\x25\x26\x27\x28\x29\x2A\x34\x35\x36"\ "\x37\x38\x39\x3A\x43\x44\x45\x46\x47\x48\x49\x4A"\ "\x53\x54\x55\x56\x57\x58\x59\x5A\x63\x64\x65\x66"\ "\x67\x68\x69\x6A\x73\x74\x75\x76\x77\x78\x79\x7A"\ "\x83\x84\x85\x86\x87\x88\x89\x8A\x92\x93\x94\x95"\ "\x96\x97\x98\x99\x9A\xA2\xA3\xA4\xA5\xA6\xA7\xA8"\ "\xA9\xAA\xB2\xB3\xB4\xB5\xB6\xB7\xB8\xB9\xBA\xC2"\ "\xC3\xC4\xC5\xC6\xC7\xC8\xC9\xCA\xD2\xD3\xD4\xD5"\ "\xD6\xD7\xD8\xD9\xDA\xE1\xE2\xE3\xE4\xE5\xE6\xE7"\ "\xE8\xE9\xEA\xF1\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9"\ "\xFA\x11\x00\x02\x01\x02\x04\x04\x03\x04\x07\x05"\ "\x04\x04\x00\x01\x02\x77\x00\x01\x02\x03\x11\x04"\ "\x05\x21\x31\x06\x12\x41\x51\x07\x61\x71\x13\x22"\ "\x32\x81\x08\x14\x42\x91\xA1\xB1\xC1\x09\x23\x33"\ "\x52\xF0\x15\x62\x72\xD1\x0A\x16\x24\x34\xE1\x25"\ "\xF1\x17\x18\x19\x1A\x26\x27\x28\x29\x2A\x35\x36"\ "\x37\x38\x39\x3A\x43\x44\x45\x46\x47\x48\x49\x4A"\ "\x53\x54\x55\x56\x57\x58\x59\x5A\x63\x64\x65\x66"\ "\x67\x68\x69\x6A\x73\x74\x75\x76\x77\x78\x79\x7A"\ "\x82\x83\x84\x85\x86\x87\x88\x89\x8A\x92\x93\x94"\ "\x95\x96\x97\x98\x99\x9A\xA2\xA3\xA4\xA5\xA6\xA7"\ "\xA8\xA9\xAA\xB2\xB3\xB4\xB5\xB6\xB7\xB8\xB9\xBA"\ "\xC2\xC3\xC4\xC5\xC6\xC7\xC8\xC9\xCA\xD2\xD3\xD4"\ "\xD5\xD6\xD7\xD8\xD9\xDA\xE2\xE3\xE4\xE5\xE6\xE7"\ "\xE8\xE9\xEA\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9\xFA" ) def read_headers(filename,size=65536): h = None f = open(filename,'rb') if f: h = f.read(size) return (f, h) def read_le32(f): h = f.read(4) s = struct.unpack("1: print "Total number of frames: %d" % (info['frames']) print "Total read: %d" % n_frame_data # # Some AVI have an index to frame, at the end of the file. This can speed up a # lot, when doing fast forward/backward. But sometimes, the pos is not from the # beginning of the file, but from the start of the movie # def read_idx(f, info, size): info['frames_offsets'] = [] n = size/16 if n<1: return None while n: tag = f.read(4) flags = read_le32(f) pos = read_le32(f) len = read_le32(f) if tag == '00dc': info['frames_offsets'].append(pos, len) #print "Tag: %s; flags=%8.8x; pos=%8d; len=%8d" % (tag, flags, pos, len) n-=1 return 1 # # Is this file have an index ?, so loaded # def find_n_read_idx(f, info): f.seek(12, 0) while True: tag = f.read(4) if len(tag)<4: return None tag_size = read_le32(f) #print "Tag: %s (len=%8d)" % (tag, tag_size) if tag == 'idx1': return read_idx(f, info, tag_size) else: if tag_size&1: tag_size+=1 f.seek(tag_size, 1) return None # # Copy the Jpeg data from the stream to out # In MJPEG, many stream don't include the huffman table. # We need to parse the JPEG stream header to find if we need to add a default huffman table. # def fix_n_output_jpeg(h, out): has_huffmantable = 0 i = 2 while True: # Hum, this is not a valid chunk if h[i] != "\xff": return None i+=1 # Skip any padding ff byte (this normal) while h[i] == 0xff: i+=1 # All SOF0 to SOF15 is valid (for me) not sure #print "Found marker %2.2x at index %d"% (ord(h[i]),i) if h[i] =='\xc4': has_huffmantable = 1 if h[i] == '\xda': # Need to flush all the file if has_huffmantable: out.write(h) else: out.write(h[0:i-1]) out.write(huffman_table) out.write(h[i-1:]) return i+=1 # Skip to next marker s = struct.unpack(">H", h[i:i+2]) i += s[0] # # Extract one image from the file # def extract_jpeg_file(moviefile, info, outfile, frame): f = open(moviefile, 'rb') # Build a cache if not info.has_key('frames_offsets'): build_cache(f, info) # Seek and copy the frame data into the file try: (offset, size) = info['frames_offsets'][frame] except IndexError: print "Warning: trying to grab frame %d but this frame is not found in the movie" % frame print "Perhaps, the file is too short" (offset, size) = info['frames_offsets'][len(info['frames_offsets'])-1] f.seek(offset,0) out = open(outfile, "wb") h = f.read(size) f.close() if h[0:2] == '\xff\xd8': # To be sure that we extract a Jpeg file fix_n_output_jpeg(h, out) else: print "Warning: this is not a jpeg file (frame=%d)" % frame out.close() def __identify(filename): if struct.calcsize(">L") != 4: print "A long is not equal to 4 bytes with your python installation. Abording" return None f, h = read_headers(filename,12) if h == None: return None if h[0:4] != 'RIFF': # RIFF header return None # 4-8 Filesize if h[8:12] != 'AVI ': # Avi chunk return None info = {} stream_index = -1 # Current Stream Header currently parsing [0...n_streams] us_frame = 0 current_codec_type = None video_codec = None info['video_size'] = (0,0) info['frames'] = 0 info['format'] = None while True: tag = f.read(4) if len(tag)<4: return None tag_size = read_le32(f) if avi_verbose>0: print "Tag \"%s\" length=%d" % (tag, tag_size) if tag == 'LIST': if avi_verbose>0: print "Type LIST" stag = f.read(4) if stag == 'movi': info['movie_end'] = f.tell() + tag_size - 4 info['movie_start'] = f.tell() if avi_verbose>0: print " movie_end at %d" % info['movie_end'] break else: if avi_verbose>0: print " ignoring unknown subtag ", stag #f.seek(tag_size-4, 1) elif tag == 'avih': if avi_verbose>0: print "Type AVI header" us_frame = read_le32(f) # in microsecond bit_rate = read_le32(f) * 8 pad_gran = read_le32(f) flags = read_le32(f) info['frames'] = read_le32(f) init_frames = read_le32(f) n_streams = read_le32(f) f.seek(tag_size-7*4, 1) if avi_verbose>0: print " us_frame = %d" % us_frame print " bit_rate = %d" % bit_rate print " flags = %x" % flags print " total frames = %d" % info['frames'] print " init_frames = %d" % init_frames print " n_streams = %d" % n_streams elif tag == 'strh': if avi_verbose>0: print "Type Stream Header" stream_index+=1 stag = f.read(4) if stag == "vids": if avi_verbose>0: print " subtag 'vids'" current_codec_type = "VIDEO" codec_tag = f.read(4) flags = read_le32(f) priority_n_language = read_le32(f) inital_frame = read_le32(f) scale= read_le32(f) rate= read_le32(f) if scale and rate: frame_rate = rate frame_rate_base = scale elif us_frame: frame_rate = 1000000 frame_rate_base = us_frame else: frame_rate = 25 frame_rate_base = 1 f.seek(tag_size-7*4, 1) if avi_verbose>0: print " codec_tag = ", codec_tag print " flags = %x" % flags print " scale = %d" % scale print " rate = %d" % rate print " frame_rate = %d / frame_rate_base = %d" % (frame_rate, frame_rate_base) # Only mjpeg is supported if codec_tag != 'mjpg': return None elif stag == "auds": if avi_verbose>0: print " subtag 'auds'" current_codec_type = "AUDIO" f.seek(tag_size-4, 1) else: if avi_verbose>0: print "Unknown subtag %s for type 'strh'" % stag return None elif tag == 'strf': if current_codec_type == "VIDEO": stream_length = read_le32(f) stream_width = read_le32(f) stream_height = read_le32(f) f.seek(4, 1) video_codec = f.read(4) #f.seek(5*4, 1) #video_extra_huffmantable = f.read(tag_size - 10*4) f.seek(tag_size-5*4, 1) info['video_size'] = (stream_width, stream_height) if avi_verbose>0: print " stream_length = %d" % stream_length print " stream size = %dx%d" % info['video_size'] print " Video Codec = %s" % video_codec elif current_codec_type == "AUDIO": f.seek(tag_size, 1) else: if avi_verbose>0: print "Unknown codec_type for Stream Format" return None else: if avi_verbose>0: print "Unknow header ", tag if tag_size&1: tag_size+=1 f.seek(tag_size,1) f.close() if video_codec == "MJPG": info['format'] = "MJPG" return info print "video_codec: ", video_codec return None def identify(filename): return __identify(filename) def extract_random_picture(moviefile, pictfile): video = __identify(moviefile) if video == None: return None r = randrange(0, video['frames']) extract_jpeg_file(moviefile, video, pictfile, r) return True def extract_picture(moviefile, pictfile, frame): video = __identify(moviefile) if video == None: return None extract_jpeg_file(moviefile, video, pictfile, frame) return True if __name__ == "__main__": import sys import AVI if len(sys.argv) < 2: print 'Usage: %s files...\n' % sys.argv[0] sys.exit(0) for filename in sys.argv[1:]: info=AVI.identify(filename) if info != None: print "%s (format='%s', frames='%d')" % (filename,info['format'],info['frames']) for frame in xrange(info['frames']): extract_jpeg_file(filename, info, "/tmp/photon%8.8d.jpg" % frame, frame) else: print "%s is not a AVI movie file" % filename