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IEC61937 detection with ffmpeg #7

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IEC61937 detection with ffmpeg #7

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85bde80
first test
Shulyaka Sep 30, 2021
194902b
Merge branch 'ffmpeg_block_validation' into ffmpeg_block_validation_2
Shulyaka Oct 5, 2021
4df5ec6
removed redundant return
Shulyaka Oct 5, 2021
c7dcffd
fix warning
Shulyaka Oct 6, 2021
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128 changes: 35 additions & 93 deletions pareceive.c
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Original file line number Diff line number Diff line change
Expand Up @@ -540,7 +540,7 @@ void open_output_stream(void)
out_sample_spec.rate = avcodeccontext->sample_rate;
out_sample_spec.channels = avcodeccontext->channels;
map_channel_layout(&out_channel_map, avcodeccontext->channel_layout);
tlength = avformatcontext->pb->buffer_size / 4 * out_bytes_per_sample * 2;
tlength = avformatcontext->pb->buffer_size / 4 * out_bytes_per_sample * 2; //block length??????????
}
else
{
Expand Down Expand Up @@ -590,8 +590,23 @@ void open_output_stream(void)
fprintf(stderr, "pa_stream_connect_playback() failed: %s\n", pa_strerror(pa_context_errno(context)));
quit(1);
}
}

return;
void set_instream_fragsize(uint32_t fragsize)
{
if(instream)
{
pa_buffer_attr buffer_attr;
memcpy(&buffer_attr, pa_stream_get_buffer_attr(instream), sizeof(pa_buffer_attr));
buffer_attr.fragsize = fragsize;
pa_operation_unref(pa_stream_set_buffer_attr(instream, &buffer_attr, stream_set_buffer_attr_callback, NULL));
}
else
{
stdin_fragsize = fragsize == (uint32_t) -1 ? MAX_STDIN_READ : fragsize;
if(stdin_fragsize > MAX_STDIN_READ)
stdin_fragsize = MAX_STDIN_READ;
}
}

static int readFunction(void* opaque, uint8_t* buf, int buf_size)
Expand Down Expand Up @@ -622,6 +637,8 @@ static int readFunction(void* opaque, uint8_t* buf, int buf_size)
inbuffer_index = 0;
}

set_instream_fragsize(buf_size);

return l;
}

Expand All @@ -636,23 +653,6 @@ void print_averror(const char *str, int err)
fprintf(stderr, "%s: %s\n", str, errbuf_ptr);
}

void set_instream_fragsize(uint32_t fragsize)
{
if(instream)
{
pa_buffer_attr buffer_attr;
memcpy(&buffer_attr, pa_stream_get_buffer_attr(instream), sizeof(pa_buffer_attr));
buffer_attr.fragsize = fragsize;
pa_operation_unref(pa_stream_set_buffer_attr(instream, &buffer_attr, stream_set_buffer_attr_callback, NULL));
}
else
{
stdin_fragsize = fragsize == (uint32_t) -1 ? MAX_STDIN_READ : fragsize;
if(stdin_fragsize > MAX_STDIN_READ)
stdin_fragsize = MAX_STDIN_READ;
}
}

void set_state(enum state newstate)
{
enum state oldstate = state;
Expand Down Expand Up @@ -727,67 +727,15 @@ void set_state(enum state newstate)
}
}

#define SPDIF_MAX_OFFSET 16384*10

// returns 0 if data is too small for examination, 1 if validation fails and a block size (aka offset) if validation is successful
size_t iec61937_validate(const uint8_t* data, size_t length)
{
static const uint32_t magic = 0x4E1FF872;
size_t firstmagic, secondmagic;

for(firstmagic = 0; firstmagic < length-sizeof(uint32_t)+1; firstmagic++)
if(*(uint32_t*)(data+firstmagic) == magic)
break;

if(firstmagic == length-sizeof(uint32_t)+1)
{
if(length < SPDIF_MAX_OFFSET)
return 0;
else
return 1;
}

for(secondmagic = firstmagic + ((*(uint16_t*)(data+firstmagic+6))>>3) + 8; secondmagic < length-sizeof(uint32_t)+1; secondmagic++)
if(*(uint32_t*)(data+secondmagic) == magic)
break;

if(secondmagic == length-sizeof(uint32_t)+1)
{
if(length < SPDIF_MAX_OFFSET * 2)
return 0;
else
return 1;
}

secondmagic -= firstmagic;

if(secondmagic > SPDIF_MAX_OFFSET)
return 1;

if(length < secondmagic * 2)
return 0;

return secondmagic;
}

//returns 1 if magic found, 0 if not
int iec61937_suspect(const uint8_t* data, size_t length)
{
static const uint32_t magic = 0x4E1FF872;
size_t firstmagic;

for(firstmagic = 0; firstmagic < length-sizeof(uint32_t)+1; firstmagic++)
if(*(uint32_t*)(data+firstmagic) == magic)
break;

return (firstmagic == length-sizeof(uint32_t)+1) ? 0 : 1;
}
#define SPDIF_MAX_OFFSET 24576

/* Process new data */
static void decode_data(const void *data, size_t length, void *userdata)
{
int i=0;
static size_t prevextralength = 0;
static AVProbeData iec61937_probedata = {0};
static int (*spdif_probe)(const AVProbeData *) = NULL;

assert(data);
assert(length > 0);
Expand Down Expand Up @@ -832,37 +780,29 @@ static void decode_data(const void *data, size_t length, void *userdata)

if(!avformatcontext)
{
size_t block_size = iec61937_validate((uint8_t*) inbuffer + inbuffer_index, inbuffer_length);
if (block_size == 0)
if(inbuffer_length < SPDIF_MAX_OFFSET)
{
#ifdef DEBUG_LATENCY
fprintf(stderr, "Buffer is too small, waiting for more data\n");
#endif
return;
}
else if(block_size == 1)

if(!spdif_probe)
spdif_probe = av_find_input_format("spdif")->read_probe;
iec61937_probedata.buf = (uint8_t*) inbuffer + inbuffer_index;
iec61937_probedata.buf_size = inbuffer_length;
if(!spdif_probe(&iec61937_probedata))
{
fprintf(stderr, "IEC61937 validation failed\n");
set_state(PCM);
return;
}

#ifdef DEBUG_LATENCY
fprintf(stderr, "block_size=%zu\n", block_size);
#endif

if(inbuffer_length < block_size * 3)
{
#ifdef DEBUG_LATENCY
fprintf(stderr, "Buffer is too small, waiting for more data\n");
#endif
return;
}

prevextralength = inbuffer_length;

avformatcontext = avformat_alloc_context();
avformatcontext->pb = avio_alloc_context(av_malloc(block_size), block_size, 0, NULL, readFunction, NULL, NULL);
avformatcontext->pb = avio_alloc_context(av_malloc(SPDIF_MAX_OFFSET), SPDIF_MAX_OFFSET, 0, NULL, readFunction, NULL, NULL);
if( (i = avformat_open_input(&avformatcontext, input_device_name, av_find_input_format("spdif"), NULL)) < 0)
{
print_averror("avformat_open_input", i);
Expand Down Expand Up @@ -922,8 +862,6 @@ static void decode_data(const void *data, size_t length, void *userdata)
pkt->data = NULL;
pkt->size = 0;

set_instream_fragsize(block_size * 2);

open_output_stream();

char buf[256];
Expand Down Expand Up @@ -1009,7 +947,11 @@ static void decode_data(const void *data, size_t length, void *userdata)

if(state==PCM)
{
if(iec61937_suspect(data, length))
if(!spdif_probe)
spdif_probe = av_find_input_format("spdif")->read_probe;
iec61937_probedata.buf = (unsigned char *)data;
iec61937_probedata.buf_size = length;
if(spdif_probe(&iec61937_probedata))
{
printf("Suspected IEC61937\n");
set_state(IEC61937);
Expand Down