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use sample aspect ratio (SAR) for thumb size calculations #96

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use sample aspect ratio (SAR) for thumb size calculations #96

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94 changes: 59 additions & 35 deletions vod/thumb/thumb_grabber.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
#include <libavcodec/avcodec.h>

#if (VOD_HAVE_LIB_SW_SCALE)
#include <math.h>
#include <libswscale/swscale.h>
#include <libavutil/imgutils.h>
#endif // VOD_HAVE_LIB_SW_SCALE
Expand All @@ -14,6 +15,8 @@ typedef struct {
request_context_t* request_context;
write_callback_t write_callback;
void* write_context;
uint32_t requested_width;
uint32_t requested_height;

// libavcodec
AVCodecContext* decoder;
Expand Down Expand Up @@ -301,8 +304,6 @@ thumb_grabber_init_state(
thumb_grabber_state_t* state;
vod_pool_cleanup_t* cln;
vod_status_t rc;
uint32_t output_width;
uint32_t output_height;
uint32_t frame_index;

if (decoder_codec[track->media_info.codec_id] == NULL) {
Expand Down Expand Up @@ -365,39 +366,8 @@ thumb_grabber_init_state(
if (rc != VOD_OK) {
return rc;
}

if (request_params->width != 0) {
output_width = request_params->width;
if (request_params->height != 0) {
output_height = request_params->height;
} else {
output_height = ((uint64_t)track->media_info.u.video.height * request_params->width)
/ track->media_info.u.video.width;
}
} else {
if (request_params->height != 0) {
output_width = ((uint64_t)track->media_info.u.video.width * request_params->height)
/ track->media_info.u.video.height;
output_height = request_params->height;
} else {
output_width = track->media_info.u.video.width;
output_height = track->media_info.u.video.height;
}
}

if (output_width <= 0 || output_height <= 0) {
vod_log_error(
VOD_LOG_ERR, request_context->log, 0, "thumb_grabber_init_state: output width/height is zero"
);
return VOD_BAD_REQUEST;
}

// TODO: postpone the initialization of the encoder to after a frame is decoded

rc = thumb_grabber_init_encoder(request_context, output_width, output_height, &state->encoder);
if (rc != VOD_OK) {
return rc;
}
state->requested_width = request_params->width;
state->requested_height = request_params->height;

state->decoded_frame = av_frame_alloc();
if (state->decoded_frame == NULL) {
Expand Down Expand Up @@ -553,6 +523,52 @@ thumb_grabber_decode_frame(thumb_grabber_state_t* state, u_char* buffer) {
return VOD_OK;
}

vod_status_t
thumb_grabber_init_encoder_internal(thumb_grabber_state_t* state)
{
int output_width, output_height;
#if (VOD_HAVE_LIB_SW_SCALE)
AVRational aspect = state->decoder->sample_aspect_ratio;
if (aspect.num == 0 || aspect.den == 0) {
aspect.num = 1;
aspect.den = 1;
}
double aspect_d = (double)aspect.num / (double)aspect.den;
if (state->requested_width != 0)
{
output_width = state->requested_width;
if (state->requested_height != 0)
{
output_height = state->requested_height;
}
else
{
output_height = lround(
((double)(state->decoded_frame->height * state->requested_width))
/ ((double)state->decoded_frame->width * aspect_d)
);
}
}
else if (state->requested_height != 0)
{
output_height = state->requested_height;
output_width = lround(
((double)(state->decoded_frame->width * state->requested_height) * aspect_d)
/ (double)state->decoded_frame->height
);
}
else
{
output_width = lround((double)state->decoded_frame->width * aspect_d);
output_height = state->decoded_frame->height;
}
#else
output_width = state->decoded_frame.width;
output_height = state->decoded_frame.height;
#endif
return thumb_grabber_init_encoder(state->request_context, output_width, output_height, &state->encoder);
}

#if (VOD_HAVE_LIB_SW_SCALE)
static vod_status_t
thumb_grabber_resize_frame(thumb_grabber_state_t* state) {
Expand Down Expand Up @@ -655,6 +671,14 @@ thumb_grabber_write_frame(thumb_grabber_state_t* state) {
return VOD_UNEXPECTED;
}

if (!state->encoder) {
rc = thumb_grabber_init_encoder_internal(state);
if (rc != VOD_OK)
{
return rc;
}
}

#if (VOD_HAVE_LIB_SW_SCALE)
if (state->encoder->width != state->decoded_frame->width
|| state->encoder->height != state->decoded_frame->height) {
Expand Down