58 sample = (sample < 0x800) ? sample : sample | 0xf000;
59 shift = (sample & 0xf00) >> 8;
61 if (shift < 0x2 || shift > 0xd) {
63 }
else if (shift < 0x8) {
68 result = ((sample + ((256 *
shift) + 1)) << shift) - 1;
79 for (c = 0; c < 10; c++) {
82 if (c&1) offs = (80 * 6 + 80 * 16 * 0 + 3 + c*12000);
83 else offs = (80 * 6 + 80 * 16 * 3 + 3 + c*12000);
86 if (c&1) offs = (80 * 6 + 80 * 16 * 1 + 3 + c*12000);
87 else offs = (80 * 6 + 80 * 16 * 4 + 3 + c*12000);
90 if (c&1) offs = (80 * 3 + 8 + c*12000);
91 else offs = (80 * 5 + 48 + 5 + c*12000);
94 offs = (80*1 + 3 + 3);
103 return frame[offs] == t ? &frame[offs] :
NULL;
121 int size, chan,
i, j, d, of, smpls, freq,
quant, half_ch;
130 smpls = as_pack[1] & 0x3f;
131 freq = as_pack[4] >> 3 & 0x07;
132 quant = as_pack[4] & 0x07;
145 ipcm = (sys->
height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
147 if (ipcm + sys->
n_difchan > (quant == 1 ? 2 : 4)) {
153 for (chan = 0; chan < sys->
n_difchan; chan++) {
162 if (quant == 1 && i == half_ch) {
171 for (j = 0; j < 9; j++) {
172 for (d = 8; d < 80; d += 2) {
181 pcm[of * 2] = frame[d + 1];
182 pcm[of * 2 + 1] = frame[d];
184 if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
187 lc = ((uint16_t)frame[d] << 4) |
188 ((uint16_t)frame[d + 2] >> 4);
189 rc = ((uint16_t)frame[d + 1] << 4) |
190 ((uint16_t)frame[d + 2] & 0x0f);
201 pcm[of * 2] = lc & 0xff;
202 pcm[of * 2 + 1] = lc >> 8;
207 pcm[of * 2] = rc & 0xff;
208 pcm[of * 2 + 1] = rc >> 8;
227 if (!as_pack || !c->
sys) {
232 smpls = as_pack[1] & 0x3f;
233 freq = as_pack[4] >> 3 & 0x07;
234 stype = as_pack[3] & 0x1f;
235 quant = as_pack[4] & 0x07;
239 "Unrecognized audio sample rate index (%d)\n", freq);
250 ach = ((
int[4]) { 1, 0, 2, 4 })[stype];
251 if (ach == 1 && quant && freq == 2)
255 for (i = 0; i <
ach; i++) {
295 apt = frame[4] & 0x07;
296 is16_9 = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
297 (!apt && (vsc_pack[2] & 0x07) == 0x07)));
359 for (i = 0; i < c->
ach; i++) {
386 for (i = 0; i < c->
ach; i++) {
421 int64_t timestamp,
int flags)
427 int64_t max_offset = ((size - 1) / frame_size) *
frame_size;
429 offset = frame_size * timestamp;
431 if (size >= 0 && offset > max_offset)
461 #define PARTIAL_FRAME_SIZE (3 * 80) 487 unsigned state, marker_pos = 0;
495 while ((state & 0xffffff7f) != 0x1f07003f) {
500 if (state == 0x003f0700 || state == 0xff3f0700)
502 if (state == 0xff3f0701 &&
avio_tell(s->
pb) - marker_pos == 80) {
521 "Can't determine profile of DV input stream.\n");
551 }
else if (ret == 0) {
562 int64_t timestamp,
int flags)
577 unsigned marker_pos = 0;
581 int secondary_matches = 0;
586 for (i = 0; i < p->
buf_size-4; i++) {
588 if ((state & 0x0007f840) == 0x00070000) {
591 if ((state & 0xff07ff7f) == 0x1f07003f) {
593 if ((state & 0xffffff7f) == 0x1f07003f) {
599 if (state == 0x003f0700 || state == 0xff3f0700)
601 if (state == 0xff3f0701 && i - marker_pos == 80)
606 if (matches && p->
buf_size / matches < 1024 * 1024) {
607 if (matches > 4 || firstmatch ||
608 (secondary_matches >= 10 &&
609 p->
buf_size / secondary_matches < 24000))
625 .extensions =
"dv,dif",
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
int64_t avio_size(AVIOContext *s)
Get the filesize.
static int shift(int a, int b)
int64_t pos
byte position in stream, -1 if unknown
static int read_seek(AVFormatContext *ctx, int stream_index, int64_t timestamp, int flags)
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown)
int index
stream index in AVFormatContext
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
AVFormatInternal * internal
An opaque field for libavformat internal usage.
int64_t bit_rate
Total stream bitrate in bit/s, 0 if not available.
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
#define AV_CH_LAYOUT_STEREO
This struct describes the properties of an encoded stream.
uint8_t audio_buf[4][8192]
#define av_assert0(cond)
assert() equivalent, that is always enabled.
unsigned int avio_rb32(AVIOContext *s)
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
uint64_t channel_layout
Audio only.
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
const uint8_t(* audio_shuffle)[9]
int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq)
Rescale a 64-bit integer by 2 rational numbers.
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
AVDictionary * metadata
Metadata that applies to the whole file.
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
const AVDVProfile * av_dv_frame_profile(const AVDVProfile *sys, const uint8_t *frame, unsigned buf_size)
Get a DV profile for the provided compressed frame.
enum AVMediaType codec_type
General type of the encoded data.
simple assert() macros that are a bit more flexible than ISO C assert().
AVRational avg_frame_rate
Average framerate.
int flags
A combination of AV_PKT_FLAG values.
int avio_r8(AVIOContext *s)
int buf_size
Size of buf except extra allocated bytes.
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
audio channel layout utility functions
char * av_timecode_make_smpte_tc_string2(char *buf, AVRational rate, uint32_t tcsmpte, int prevent_df, int skip_field)
Get the timecode string from the SMPTE timecode format.
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
#define FF_ARRAY_ELEMS(a)
static int read_header(FFV1Context *f)
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
AVIOContext * pb
I/O context.
#define DV_MAX_FRAME_SIZE
largest possible DV frame, in bytes (1080i50)
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
Rational number (pair of numerator and denominator).
This structure contains the data a format has to probe a file.
#define flags(name, subs,...)
static av_always_inline AVRational av_inv_q(AVRational q)
Invert a rational.
int sample_rate
Audio only.
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
uint8_t buf[DV_MAX_FRAME_SIZE]
void av_init_packet(AVPacket *pkt)
Initialize optional fields of a packet with default values.
void * priv_data
Format private data.
and forward the result(frame or status change) to the corresponding input.If nothing is possible
AVCodecParameters * codecpar
Codec parameters associated with this stream.
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
#define AV_TIMECODE_STR_SIZE