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flightgear/utils/iaxclient/lib/codec_theora.c
f-jjth d03b44b662 FGCom integrated into FlightGear.
Disabled by default at build time.
2013-08-16 17:02:47 +01:00

502 lines
12 KiB
C

/*
* iaxclient: a cross-platform IAX softphone library
*
* Copyrights:
* Copyright (C) 2003-2006, Horizon Wimba, Inc.
* Copyright (C) 2007, Wimba, Inc.
*
* Contributors:
* Steve Kann <stevek@stevek.com>
* Mihai Balea <mihai at hates dot ms>
*
* This program is free software, distributed under the terms of
* the GNU Lesser (Library) General Public License.
*/
/*
* Some comments about Theora streaming
* Theora video codec has two problems when it comes to streaming
* and broadcasting video:
*
* - Large headers that need to be passed from the encoder to the decoder
* to initialize it. The conventional wisdom says we should transfer the
* headers out of band, but that complicates things with IAX, which does
* not have a separate signalling channel. Also, it makes things really
* difficult in a video conference scenario, where video gets switched
* between participants regularly. To solve this issue, we initialize
* the encoder and the decoder at the same time, using the headers from
* the local encoder to initialize the decoder. This works if the
* endpoints use the exact same version of Theora and the exact same
* parameters for initialization.
*
* - No support for splitting the frame into multiple slices. Frames can
* be relatively large. For a 320x240 video stream, you can see key
* frames larger than 9KB, which is the maximum UDP packet size on Mac
* OS X. To work around this limitation, we use the slice API to fragment
* encoded frames to a reasonable size that UDP can safely transport
*
* Other miscellaneous comments:
*
* - For quality reasons, when we detect a video stream switch, we reject all
* incoming frames until we receive a key frame.
*
* - Theora only accepts video that has dimensions multiple of 16. If we combine
* his with a 4:3 aspect ratio requirement, we get a very limited number
* of available resolutions. To work around this limitation, we pad the video
* on encoding, up to the closest multiple of 16. On the decoding side, we
* remove the padding. This way, video resolution can be any multiple of 2
*
* We should probably look more into this (how to deal with missing and
* out of order slices)
*/
#include <stdlib.h>
#include "iaxclient_lib.h"
#include "video.h"
#include "slice.h"
#include "codec_theora.h"
#include <theora/theora.h>
#define MAX_SLICE_SIZE 8000
struct theora_decoder
{
theora_state td;
theora_info ti;
theora_comment tc;
struct deslicer_context *dsc;
int got_key_frame;
};
struct theora_encoder
{
theora_state td;
theora_info ti;
theora_comment tc;
int needs_padding;
struct slicer_context *sc;
unsigned char *pad_buffer;
};
static void destroy( struct iaxc_video_codec *c)
{
struct theora_encoder *e;
struct theora_decoder *d;
if ( !c )
return;
if ( c->encstate )
{
e = (struct theora_encoder *)c->encstate;
if ( e->pad_buffer )
free(e->pad_buffer);
if ( e->sc )
free_slicer_context(e->sc);
theora_comment_clear(&e->tc);
theora_info_clear(&e->ti);
theora_clear(&e->td);
free(e);
}
if ( c->decstate )
{
d = (struct theora_decoder *)c->decstate;
if ( d->dsc )
free_deslicer_context(d->dsc);
theora_comment_clear(&d->tc);
theora_info_clear(&d->ti);
theora_clear(&d->td);
free(c->decstate);
}
free(c);
}
static int decode(struct iaxc_video_codec *c, int inlen, const char *in,
int *outlen, char *out)
{
struct theora_decoder *d;
ogg_packet op;
yuv_buffer picture;
unsigned int line;
int my_out_len;
int w, h, ph;
int flen;
char *frame;
// Sanity checks
if ( !c || !c->decstate || !in || inlen <= 0 || !out || !outlen )
return -1;
// Assemble slices
d = (struct theora_decoder *)c->decstate;
if ( !d->dsc )
return -1;
frame = deslice(in, inlen, &flen, d->dsc);
if ( frame == NULL )
return 1;
/* decode into an OP structure */
memset(&op, 0, sizeof(op));
op.bytes = flen;
op.packet = (unsigned char *)frame;
/* reject all incoming frames until we get a key frame */
if ( !d->got_key_frame )
{
if ( theora_packet_iskeyframe(&op) )
d->got_key_frame = 1;
else
return 1;
}
if ( theora_decode_packetin(&d->td, &op) == OC_BADPACKET )
{
fprintf(stderr,
"codec_theora: warning: theora_decode_packetin says bad packet\n");
return -1;
}
w = d->ti.frame_width;
h = d->ti.frame_height;
ph = d->ti.height;
my_out_len = d->ti.frame_width * d->ti.frame_height * 3 / 2;
/* make sure we have enough room for the goodies */
if ( *outlen < my_out_len )
{
fprintf(stderr, "codec_theora: not enough room for decoding\n");
return -1;
}
/* finally, here's where we get our goodies */
if ( theora_decode_YUVout(&d->td, &picture) )
{
fprintf(stderr, "codec_theora: error getting our goodies\n");
return -1;
}
//clear output
memset(out, 127, my_out_len);
for( line = 0 ; line < d->ti.frame_height / 2 ; line++ )
{
// Y-even
memcpy(out + picture.y_width * 2 * line,
picture.y + 2 * line * picture.y_stride,
picture.y_width);
// Y-odd
memcpy(out + picture.y_width * (2 * line + 1),
picture.y + (2 * line + 1) * picture.y_stride,
picture.y_width);
// U + V
memcpy(out + (d->ti.frame_width * d->ti.frame_height) + line * d->ti.frame_width / 2,
picture.u + line * picture.uv_stride,
picture.uv_width);
memcpy(out + (d->ti.frame_width * d->ti.frame_height * 5 / 4) + line * d->ti.frame_width / 2,
picture.v + line * picture.uv_stride,
picture.uv_width);
}
*outlen = my_out_len;
return 0;
}
// Pads a w by h frame to bring it up to pw by ph size using value
static void pad_channel(const char *src, int w, int h, unsigned char *dst,
int pw, int ph, unsigned char value)
{
int i;
if ( w == pw )
{
// We don't need to pad each line, just copy the data
memcpy(dst, src, w * h);
} else
{
// We DO need to pad each line
for ( i=0 ; i<h ; i++ )
{
memcpy(&dst[i*pw], &src[i*w], w);
memset(&dst[i*pw+w], value, pw-w);
}
}
// Pad the bottom of the frame if necessary
if ( h < ph )
memset(dst + pw * h, value, (ph - h) * pw);
}
static int encode(struct iaxc_video_codec * c, int inlen, const char * in,
struct slice_set_t * slice_set)
{
struct theora_encoder *e;
ogg_packet op;
yuv_buffer picture;
// Sanity checks
if ( !c || !c->encstate || !in || !slice_set )
return -1;
e = (struct theora_encoder *)c->encstate;
// Prepare the YUV buffer
if ( e->needs_padding )
{
// We copy a padded image into the pad buffer and set up the pointers
// Use pad_channel for each of the YUV channels
// Use a pad value of 0 for luma and 128 for chroma
pad_channel(in,
e->ti.frame_width,
e->ti.frame_height,
e->pad_buffer,
e->ti.width,
e->ti.height,
0);
pad_channel(in + e->ti.frame_width * e->ti.frame_height,
e->ti.frame_width / 2,
e->ti.frame_height / 2,
e->pad_buffer + e->ti.width * e->ti.height,
e->ti.width / 2,
e->ti.height / 2,
128);
pad_channel(in + e->ti.frame_width * e->ti.frame_height * 5 / 4,
e->ti.frame_width / 2,
e->ti.frame_height / 2,
e->pad_buffer + e->ti.width * e->ti.height * 5 / 4,
e->ti.width / 2,
e->ti.height / 2,
128);
picture.y = e->pad_buffer;
} else
{
// use the original buffer
picture.y = (unsigned char *)in;
}
picture.u = picture.y + e->ti.width * e->ti.height;
picture.v = picture.u + e->ti.width * e->ti.height / 4;
picture.y_width = e->ti.width;
picture.y_height = e->ti.height;
picture.y_stride = e->ti.width;
picture.uv_width = e->ti.width / 2;
picture.uv_height = e->ti.height / 2;
picture.uv_stride = e->ti.width / 2;
// Send data in for encoding
if ( theora_encode_YUVin(&e->td, &picture) )
{
fprintf(stderr, "codec_theora: failed theora_encode_YUVin\n");
return -1;
}
// Get data from the encoder
if ( theora_encode_packetout(&e->td, 0, &op) != 1 )
{
fprintf(stderr, "codec_theora: failed theora_encode_packetout\n");
return -1;
}
// Check to see if we have a key frame
slice_set->key_frame = theora_packet_iskeyframe(&op) == 1;
// Slice the frame
slice((char *)op.packet, op.bytes, slice_set, e->sc);
return 0;
}
struct iaxc_video_codec *codec_video_theora_new(int format, int w, int h,
int framerate, int bitrate, int fragsize)
{
struct iaxc_video_codec *c;
struct theora_encoder *e;
struct theora_decoder *d;
unsigned short source_id;
ogg_packet headerp, commentp, tablep;
/* Basic sanity checks */
if ( w <= 0 || h <= 0 || framerate <= 0 || bitrate <= 0 || fragsize <= 0 )
{
fprintf(stderr, "codec_theora: bogus codec params: %d %d %d %d %d\n",
w, h, framerate, bitrate, fragsize);
return NULL;
}
if ( w % 2 || h % 2 )
{
fprintf(stderr, "codec_theora: video dimensions must be multiples of 2\n");
return NULL;
}
if ( fragsize > MAX_SLICE_SIZE )
fragsize = MAX_SLICE_SIZE;
c = (struct iaxc_video_codec *)calloc(sizeof(struct iaxc_video_codec), 1);
if ( !c )
goto bail;
c->decstate = calloc(sizeof(struct theora_decoder), 1);
if ( !c->decstate )
goto bail;
c->encstate = calloc(sizeof(struct theora_encoder), 1);
if ( !c->encstate )
goto bail;
c->format = format;
c->width = w;
c->height = h;
c->framerate = framerate;
c->bitrate = bitrate;
c->fragsize = fragsize;
c->encode = encode;
c->decode = decode;
c->destroy = destroy;
e = (struct theora_encoder *)c->encstate;
d = (struct theora_decoder *)c->decstate;
// Initialize slicer
// Generate random source id
srand((unsigned int)time(0));
source_id = rand() & 0xffff;
e->sc = create_slicer_context(source_id, fragsize);
if ( !e->sc )
goto bail;
/* set up some parameters in the contexts */
theora_info_init(&e->ti);
/* set up common parameters */
e->ti.frame_width = w;
e->ti.frame_height = h;
e->ti.width = ((w - 1) / 16 + 1) * 16;
e->ti.height = ((h - 1) / 16 + 1) * 16;
e->ti.offset_x = 0;
e->ti.offset_y = 0;
// We set up a padded frame with dimensions that are multiple of 16
// We allocate a buffer to hold this frame
e->needs_padding = e->ti.width != e->ti.frame_width ||
e->ti.height != e->ti.frame_height;
if ( e->needs_padding )
{
e->pad_buffer = (unsigned char *)
malloc(e->ti.width * e->ti.height * 3 / 2);
if ( !e->pad_buffer )
goto bail;
}
else
{
e->pad_buffer = 0;
}
e->ti.fps_numerator = framerate;
e->ti.fps_denominator = 1;
e->ti.aspect_numerator = 1;
e->ti.aspect_denominator = 1;
e->ti.colorspace = OC_CS_UNSPECIFIED;
e->ti.pixelformat = OC_PF_420;
e->ti.target_bitrate = bitrate;
e->ti.quality = 0;
e->ti.dropframes_p = 0;
e->ti.quick_p = 1;
e->ti.keyframe_auto_p = 0;
e->ti.keyframe_frequency = framerate;
e->ti.keyframe_frequency_force = framerate;
e->ti.keyframe_data_target_bitrate = bitrate * 3;
e->ti.keyframe_auto_threshold = 80;
e->ti.keyframe_mindistance = 8;
e->ti.noise_sensitivity = 0;
if ( theora_encode_init(&e->td, &e->ti) )
goto bail;
// Obtain the encoder headers and set up the decoder headers from
// data in the encoder headers
memset(&headerp, 0, sizeof(headerp));
memset(&commentp, 0, sizeof(commentp));
memset(&tablep, 0, sizeof(tablep));
// Set up the decoder using the encoder headers
theora_info_init(&d->ti);
theora_comment_init(&d->tc);
theora_comment_init(&e->tc);
if ( theora_encode_header(&e->td, &headerp) )
goto bail;
headerp.b_o_s = 1;
if ( theora_decode_header(&d->ti, &d->tc, &headerp) )
goto bail;
if ( theora_encode_comment(&e->tc, &commentp) )
goto bail;
if ( theora_decode_header(&d->ti, &d->tc, &commentp) )
goto bail;
theora_comment_clear(&e->tc);
if ( theora_encode_tables(&e->td, &tablep) )
goto bail;
if ( theora_decode_header(&d->ti, &d->tc, &tablep) )
goto bail;
if ( theora_decode_init(&d->td, &d->ti) )
goto bail;
d->got_key_frame = 0;
// Initialize deslicer context
d->dsc = create_deslicer_context(c->fragsize);
if ( !d->dsc )
goto bail;
strcpy(c->name, "Theora");
return c;
bail:
fprintf(stderr, "codec_theora: failed to initialize encoder or decoder\n");
if ( c )
{
if ( c->encstate )
{
e = (struct theora_encoder *)c->encstate;
if ( e->sc )
free_slicer_context(e->sc);
free(c->encstate);
}
if ( c->decstate )
{
d = (struct theora_decoder *)c->decstate;
if ( d->dsc )
free_deslicer_context(d->dsc);
free(c->decstate);
}
free(c);
}
return NULL;
}