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lavc: add codec parameters API 

This API is intended to allow passing around codec parameters without
using full AVCodecContext (which also contains codec options and
encoder/decoder state).
This commit is contained in:
Anton Khirnov 2014-06-18 20:42:13 +02:00
parent 257b30af8e
commit 998e1b8f52
4 changed files with 319 additions and 1 deletions
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3
doc/APIchanges
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@ -13,6 +13,9 @@ libavutil: 2015-08-28
API changes, most recent first:
2016-xx-xx - lavc 57.14.0 - avcodec.h
xxxxxxx - Add AVCodecParameters and its related API.
2016-xx-xx - xxxxxxx - lavf 57.4.0 - avformat.h
Add AVFormatContext.protocol_whitelist and protocol_blacklist.
Add 'protocol_whitelist' and 'protocol_blacklist' private options for

163
libavcodec/avcodec.h
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@ -3335,6 +3335,127 @@ typedef struct AVSubtitle {
int64_t pts; ///< Same as packet pts, in AV_TIME_BASE
} AVSubtitle;
/**
* This struct describes the properties of an encoded stream.
*
* sizeof(AVCodecParameters) is not a part of the public ABI, this struct must
* be allocated with avcodec_parameters_alloc() and freed with
* avcodec_parameters_free().
*/
typedef struct AVCodecParameters {
/**
* General type of the encoded data.
*/
enum AVMediaType codec_type;
/**
* Specific type of the encoded data (the codec used).
*/
enum AVCodecID codec_id;
/**
* Additional information about the codec (corresponds to the AVI FOURCC).
*/
uint32_t codec_tag;
/**
* Extra binary data needed for initializing the decoder, codec-dependent.
*
* Must be allocated with av_malloc() and will be freed by
* avcodec_parameters_free(). The allocated size of extradata must be at
* least extradata_size + AV_INPUT_BUFFER_PADDING_SIZE, with the padding
* bytes zeroed.
*/
uint8_t *extradata;
/**
* Size of the extradata content in bytes.
*/
int extradata_size;
/**
* - video: the pixel format, the value corresponds to enum AVPixelFormat.
* - audio: the sample format, the value corresponds to enum AVSampleFormat.
*/
int format;
/**
* The average bitrate of the encoded data (in bits per second).
*/
int bit_rate;
int bits_per_coded_sample;
/**
* Codec-specific bitstream restrictions that the stream conforms to.
*/
int profile;
int level;
/**
* Video only. The dimensions of the video frame in pixels.
*/
int width;
int height;
/**
* Video only. The aspect ratio (width / height) which a single pixel
* should have when displayed.
*
* When the aspect ratio is unknown / undefined, the numerator should be
* set to 0 (the denominator may have any value).
*/
AVRational sample_aspect_ratio;
/**
* Video only. The order of the fields in interlaced video.
*/
enum AVFieldOrder field_order;
/**
* Video only. Additional colorspace characteristics.
*/
enum AVColorRange color_range;
enum AVColorPrimaries color_primaries;
enum AVColorTransferCharacteristic color_trc;
enum AVColorSpace color_space;
enum AVChromaLocation chroma_location;
/**
* Audio only. The channel layout bitmask. May be 0 if the channel layout is
* unknown or unspecified, otherwise the number of bits set must be equal to
* the channels field.
*/
uint64_t channel_layout;
/**
* Audio only. The number of audio channels.
*/
int channels;
/**
* Audio only. The number of audio samples per second.
*/
int sample_rate;
/**
* Audio only. The number of bytes per coded audio frame, required by some
* formats.
*
* Corresponds to nBlockAlign in WAVEFORMATEX.
*/
int block_align;
/**
* Audio only. The amount of padding (in samples) inserted by the encoder at
* the beginning of the audio. I.e. this number of leading decoded samples
* must be discarded by the caller to get the original audio without leading
* padding.
*/
int initial_padding;
/**
* Audio only. The amount of padding (in samples) appended by the encoder to
* the end of the audio. I.e. this number of decoded samples must be
* discarded by the caller from the end of the stream to get the original
* audio without any trailing padding.
*/
int trailing_padding;
} AVCodecParameters;
/**
* If c is NULL, returns the first registered codec,
* if c is non-NULL, returns the next registered codec after c,
@ -3433,6 +3554,48 @@ const AVClass *avcodec_get_class(void);
*/
int avcodec_copy_context(AVCodecContext *dest, const AVCodecContext *src);
/**
* Allocate a new AVCodecParameters and set its fields to default values
* (unknown/invalid/0). The returned struct must be freed with
* avcodec_parameters_free().
*/
AVCodecParameters *avcodec_parameters_alloc(void);
/**
* Free an AVCodecParameters instance and everything associated with it and
* write NULL to the supplied pointer.
*/
void avcodec_parameters_free(AVCodecParameters **par);
/**
* Copy the contents of src to dst. Any allocated fields in dst are freed and
* replaced with newly allocated duplicates of the corresponding fields in src.
*
* @return >= 0 on success, a negative AVERROR code on failure.
*/
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src);
/**
* Fill the parameters struct based on the values from the supplied codec
* context. Any allocated fields in par are freed and replaced with duplicates
* of the corresponding fields in codec.
*
* @return >= 0 on success, a negative AVERROR code on failure
*/
int avcodec_parameters_from_context(AVCodecParameters *par,
const AVCodecContext *codec);
/**
* Fill the codec context based on the values from the supplied codec
* parameters. Any allocated fields in codec that have a corresponding field in
* par are freed and replaced with duplicates of the corresponding field in par.
* Fields in codec that do not have a counterpart in par are not touched.
*
* @return >= 0 on success, a negative AVERROR code on failure.
*/
int avcodec_parameters_to_context(AVCodecContext *codec,
const AVCodecParameters *par);
/**
* Initialize the AVCodecContext to use the given AVCodec. Prior to using this
* function the context has to be allocated with avcodec_alloc_context3().

152
libavcodec/utils.c
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@ -2440,3 +2440,155 @@ AVCPBProperties *ff_add_cpb_side_data(AVCodecContext *avctx)
return props;
}
static void codec_parameters_reset(AVCodecParameters *par)
{
av_freep(&par->extradata);
memset(par, 0, sizeof(*par));
par->codec_type = AVMEDIA_TYPE_UNKNOWN;
par->codec_id = AV_CODEC_ID_NONE;
par->format = -1;
par->field_order = AV_FIELD_UNKNOWN;
par->color_range = AVCOL_RANGE_UNSPECIFIED;
par->color_primaries = AVCOL_PRI_UNSPECIFIED;
par->color_trc = AVCOL_TRC_UNSPECIFIED;
par->color_space = AVCOL_SPC_UNSPECIFIED;
par->chroma_location = AVCHROMA_LOC_UNSPECIFIED;
par->sample_aspect_ratio = (AVRational){ 0, 1 };
}
AVCodecParameters *avcodec_parameters_alloc(void)
{
AVCodecParameters *par = av_mallocz(sizeof(*par));
if (!par)
return NULL;
codec_parameters_reset(par);
return par;
}
void avcodec_parameters_free(AVCodecParameters **ppar)
{
AVCodecParameters *par = *ppar;
if (!par)
return;
codec_parameters_reset(par);
av_freep(ppar);
}
int avcodec_parameters_copy(AVCodecParameters *dst, const AVCodecParameters *src)
{
codec_parameters_reset(dst);
memcpy(dst, src, sizeof(*dst));
dst->extradata = NULL;
dst->extradata_size = 0;
if (src->extradata) {
dst->extradata = av_mallocz(src->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!dst->extradata)
return AVERROR(ENOMEM);
memcpy(dst->extradata, src->extradata, src->extradata_size);
dst->extradata_size = src->extradata_size;
}
return 0;
}
int avcodec_parameters_from_context(AVCodecParameters *par,
const AVCodecContext *codec)
{
codec_parameters_reset(par);
par->codec_type = codec->codec_type;
par->codec_id = codec->codec_id;
par->codec_tag = codec->codec_tag;
par->bit_rate = codec->bit_rate;
par->bits_per_coded_sample = codec->bits_per_coded_sample;
par->profile = codec->profile;
par->level = codec->level;
switch (par->codec_type) {
case AVMEDIA_TYPE_VIDEO:
par->format = codec->pix_fmt;
par->width = codec->width;
par->height = codec->height;
par->field_order = codec->field_order;
par->color_range = codec->color_range;
par->color_primaries = codec->color_primaries;
par->color_trc = codec->color_trc;
par->color_space = codec->colorspace;
par->chroma_location = codec->chroma_sample_location;
par->sample_aspect_ratio = codec->sample_aspect_ratio;
break;
case AVMEDIA_TYPE_AUDIO:
par->format = codec->sample_fmt;
par->channel_layout = codec->channel_layout;
par->channels = codec->channels;
par->sample_rate = codec->sample_rate;
par->block_align = codec->block_align;
par->initial_padding = codec->initial_padding;
break;
}
if (codec->extradata) {
par->extradata = av_mallocz(codec->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!par->extradata)
return AVERROR(ENOMEM);
memcpy(par->extradata, codec->extradata, codec->extradata_size);
par->extradata_size = codec->extradata_size;
}
return 0;
}
int avcodec_parameters_to_context(AVCodecContext *codec,
const AVCodecParameters *par)
{
codec->codec_type = par->codec_type;
codec->codec_id = par->codec_id;
codec->codec_tag = par->codec_tag;
codec->bit_rate = par->bit_rate;
codec->bits_per_coded_sample = par->bits_per_coded_sample;
codec->profile = par->profile;
codec->level = par->level;
switch (par->codec_type) {
case AVMEDIA_TYPE_VIDEO:
codec->pix_fmt = par->format;
codec->width = par->width;
codec->height = par->height;
codec->field_order = par->field_order;
codec->color_range = par->color_range;
codec->color_primaries = par->color_primaries;
codec->color_trc = par->color_trc;
codec->colorspace = par->color_space;
codec->chroma_sample_location = par->chroma_location;
codec->sample_aspect_ratio = par->sample_aspect_ratio;
break;
case AVMEDIA_TYPE_AUDIO:
codec->sample_fmt = par->format;
codec->channel_layout = par->channel_layout;
codec->channels = par->channels;
codec->sample_rate = par->sample_rate;
codec->block_align = par->block_align;
codec->initial_padding = par->initial_padding;
break;
}
if (par->extradata) {
av_freep(&codec->extradata);
codec->extradata = av_mallocz(par->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
if (!codec->extradata)
return AVERROR(ENOMEM);
memcpy(codec->extradata, par->extradata, par->extradata_size);
codec->extradata_size = par->extradata_size;
}
return 0;
}

2
libavcodec/version.h
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@ -28,7 +28,7 @@
#include "libavutil/version.h"
#define LIBAVCODEC_VERSION_MAJOR 57
#define LIBAVCODEC_VERSION_MINOR 13
#define LIBAVCODEC_VERSION_MINOR 14
#define LIBAVCODEC_VERSION_MICRO 0
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \