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author | John Koleszar <jkoleszar@google.com> | 2011-05-20 00:05:16 -0400 |
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committer | John Koleszar <jkoleszar@google.com> | 2011-05-20 00:05:16 -0400 |
commit | 27331e1377465aad1d97f9796dca56542ba389af (patch) | |
tree | e752f334e7c90cc48dbc81cdce81554bdba65791 /examples | |
parent | e05fd0fc36ef7e17be6dc87a7ff2ae72a5fa2473 (diff) | |
parent | 1f3f18443db5820157448515579c14efd19eea1b (diff) | |
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Merge remote branch 'internal/upstream' into HEAD
Diffstat (limited to 'examples')
-rw-r--r-- | examples/decode_with_partial_drops.txt | 232 | ||||
-rw-r--r-- | examples/decoder_tmpl.c | 2 |
2 files changed, 234 insertions, 0 deletions
diff --git a/examples/decode_with_partial_drops.txt b/examples/decode_with_partial_drops.txt new file mode 100644 index 000000000..30854d669 --- /dev/null +++ b/examples/decode_with_partial_drops.txt @@ -0,0 +1,232 @@ +@TEMPLATE decoder_tmpl.c +Decode With Partial Drops Example +========================= +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION +This is an example utility which drops a series of frames (or parts of frames), +as specified on the command line. This is useful for observing the error +recovery features of the codec. +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ INTRODUCTION + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_INCLUDES +#include <time.h> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_INCLUDES + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELPERS +struct parsed_header +{ + char key_frame; + int version; + char show_frame; + int first_part_size; +}; + +int next_packet(struct parsed_header* hdr, int pos, int length, int mtu) +{ + int size = 0; + int remaining = length - pos; + /* Uncompressed part is 3 bytes for P frames and 10 bytes for I frames */ + int uncomp_part_size = (hdr->key_frame ? 10 : 3); + /* number of bytes yet to send from header and the first partition */ + int remainFirst = uncomp_part_size + hdr->first_part_size - pos; + if (remainFirst > 0) + { + if (remainFirst <= mtu) + { + size = remainFirst; + } + else + { + size = mtu; + } + + return size; + } + + /* second partition; just slot it up according to MTU */ + if (remaining <= mtu) + { + size = remaining; + return size; + } + return mtu; +} + +void throw_packets(unsigned char* frame, int* size, int loss_rate, + int* thrown, int* kept) +{ + unsigned char loss_frame[256*1024]; + int pkg_size = 1; + int pos = 0; + int loss_pos = 0; + struct parsed_header hdr; + unsigned int tmp; + int mtu = 1500; + + if (*size < 3) + { + return; + } + putc('|', stdout); + /* parse uncompressed 3 bytes */ + tmp = (frame[2] << 16) | (frame[1] << 8) | frame[0]; + hdr.key_frame = !(tmp & 0x1); /* inverse logic */ + hdr.version = (tmp >> 1) & 0x7; + hdr.show_frame = (tmp >> 4) & 0x1; + hdr.first_part_size = (tmp >> 5) & 0x7FFFF; + + /* don't drop key frames */ + if (hdr.key_frame) + { + int i; + *kept = *size/mtu + ((*size % mtu > 0) ? 1 : 0); /* approximate */ + for (i=0; i < *kept; i++) + putc('.', stdout); + return; + } + + while ((pkg_size = next_packet(&hdr, pos, *size, mtu)) > 0) + { + int loss_event = ((rand() + 1.0)/(RAND_MAX + 1.0) < loss_rate/100.0); + if (*thrown == 0 && !loss_event) + { + memcpy(loss_frame + loss_pos, frame + pos, pkg_size); + loss_pos += pkg_size; + (*kept)++; + putc('.', stdout); + } + else + { + (*thrown)++; + putc('X', stdout); + } + pos += pkg_size; + } + memcpy(frame, loss_frame, loss_pos); + memset(frame + loss_pos, 0, *size - loss_pos); + *size = loss_pos; +} +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELPERS + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DEC_INIT +/* Initialize codec */ +flags = VPX_CODEC_USE_ERROR_CONCEALMENT; +res = vpx_codec_dec_init(&codec, interface, NULL, flags); +if(res) + die_codec(&codec, "Failed to initialize decoder"); + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ DEC_INIT + +Usage +----- +This example adds a single argument to the `simple_decoder` example, +which specifies the range or pattern of frames to drop. The parameter is +parsed as follows: + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ USAGE +if(argc!=4 && argc != 5) + die("Usage: %s <infile> <outfile> <N-M|N/M|L,S>\n", argv[0]); +{ + char *nptr; + n = strtol(argv[3], &nptr, 0); + mode = (*nptr == '\0' || *nptr == ',') ? 2 : (*nptr == '-') ? 1 : 0; + + m = strtol(nptr+1, NULL, 0); + if((!n && !m) || (*nptr != '-' && *nptr != '/' && + *nptr != '\0' && *nptr != ',')) + die("Couldn't parse pattern %s\n", argv[3]); +} +seed = (m > 0) ? m : (unsigned int)time(NULL); +srand(seed);thrown_frame = 0; +printf("Seed: %u\n", seed); +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ USAGE + + +Dropping A Range Of Frames +-------------------------- +To drop a range of frames, specify the starting frame and the ending +frame to drop, separated by a dash. The following command will drop +frames 5 through 10 (base 1). + + $ ./decode_with_partial_drops in.ivf out.i420 5-10 + + +Dropping A Pattern Of Frames +---------------------------- +To drop a pattern of frames, specify the number of frames to drop and +the number of frames after which to repeat the pattern, separated by +a forward-slash. The following command will drop 3 of 7 frames. +Specifically, it will decode 4 frames, then drop 3 frames, and then +repeat. + + $ ./decode_with_partial_drops in.ivf out.i420 3/7 + +Dropping Random Parts Of Frames +------------------------------- +A third argument tuple is available to split the frame into 1500 bytes pieces +and randomly drop pieces rather than frames. The frame will be split at +partition boundaries where possible. The following example will seed the RNG +with the seed 123 and drop approximately 5% of the pieces. Pieces which +are depending on an already dropped piece will also be dropped. + + $ ./decode_with_partial_drops in.ivf out.i420 5,123 + + +Extra Variables +--------------- +This example maintains the pattern passed on the command line in the +`n`, `m`, and `is_range` variables: + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_VARS +int n, m, mode; +unsigned int seed; +int thrown=0, kept=0; +int thrown_frame=0, kept_frame=0; +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ EXTRA_VARS + + +Making The Drop Decision +------------------------ +The example decides whether to drop the frame based on the current +frame number, immediately before decoding the frame. + +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE +/* Decide whether to throw parts of the frame or the whole frame + depending on the drop mode */ +thrown_frame = 0; +kept_frame = 0; +switch (mode) +{ +case 0: + if (m - (frame_cnt-1)%m <= n) + { + frame_sz = 0; + } + break; +case 1: + if (frame_cnt >= n && frame_cnt <= m) + { + frame_sz = 0; + } + break; +case 2: + throw_packets(frame, &frame_sz, n, &thrown_frame, &kept_frame); + break; +default: break; +} +if (mode < 2) +{ + if (frame_sz == 0) + { + putc('X', stdout); + thrown_frame++; + } + else + { + putc('.', stdout); + kept_frame++; + } +} +thrown += thrown_frame; +kept += kept_frame; +fflush(stdout); +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRE_DECODE diff --git a/examples/decoder_tmpl.c b/examples/decoder_tmpl.c index c70681b1a..8194f0ade 100644 --- a/examples/decoder_tmpl.c +++ b/examples/decoder_tmpl.c @@ -42,6 +42,8 @@ static void die(const char *fmt, ...) { @DIE_CODEC +@HELPERS + int main(int argc, char **argv) { FILE *infile, *outfile; vpx_codec_ctx_t codec; |