ffmpeg之AVFrame
目录
结构体说明
原始数据的相关信息结构体
/**
* This structure describes decoded (raw) audio or video data.
* 此结构描述解码后的（未编码前的）原始音频或者视频数据
* AVFrame must be allocated using av_frame_alloc(). Note that this only
* allocates the AVFrame itself, the buffers for the data must be managed
* through other means (see below).
* AVFrame must be freed with av_frame_free().
* AVFrame必须使用av_frame_alloc进行分配，重点是只会分配AVFrame本身，不会分配存储真实数据的buffer
* AVFrame必须使用av_frame_free进行释放。
* AVFrame is typically allocated once and then reused multiple times to hold
* different data (e.g. a single AVFrame to hold frames received from a
* decoder). In such a case, av_frame_unref() will free any references held by
* the frame and reset it to its original clean state before it
* is reused again.
* AVFrame通常一次分配，多次使用（while前alloc，后free，内部多次使用，av_frame_unref会释放buffe的所有引用，并将其置为原始干净状态，然后再次使用）
* The data described by an AVFrame is usually reference counted through the
* AVBuffer API. The underlying buffer references are stored in AVFrame.buf /
* AVFrame.extended_buf. An AVFrame is considered to be reference counted if at
* least one reference is set, i.e. if AVFrame.buf[0] != NULL. In such a case,
* every single data plane must be contained in one of the buffers in
* AVFrame.buf or AVFrame.extended_buf.
* There may be a single buffer for all the data, or one separate buffer for
* each plane, or anything in between.
* AVFrame的原始数据有引用计数进行内存管理；
* 对于planar存储的数据格式，多通道数据存储在二维数组data中
* sizeof(AVFrame) is not a part of the public ABI, so new fields may be added
* to the end with a minor bump.
*
* Fields can be accessed through AVOptions, the name string used, matches the
* C structure field name for fields accessible through AVOptions. The AVClass
* for AVFrame can be obtained from avcodec_get_frame_class()
*/
typedef struct AVFrame {
#define AV_NUM_DATA_POINTERS 8
/**
* pointer to the picture/channel planes.
* This might be different from the first allocated byte
*
* Some decoders access areas outside 0,0 - width,height, please
* see avcodec_align_dimensions2(). Some filters and swscale can read
* up to 16 bytes beyond the planes, if these filters are to be used,
* then 16 extra bytes must be allocated.
*
* NOTE: Except for hwaccel formats, pointers not needed by the format
* MUST be set to NULL.
* 编码前的原始图片或者声音数据，最多存储8个通道的数据
*/
uint8_t *data[AV_NUM_DATA_POINTERS];
/**
* For video, size in bytes of each picture line.
* For audio, size in bytes of each plane.
* 对于视频，每张图片行的大小（以字节为单位）
* 对应音频，每个通道的大小（以字节为单位）
* For audio, only linesize[0] may be set. For planar audio, each channel
* plane must be the same size.
* 对于音频，智能设置linesize[0],对于planar，每个通道必须相同的linesize
* For video the linesizes should be multiples of the CPUs alignment
* preference, this is 16 or 32 for modern desktop CPUs.
* Some code requires such alignment other code can be slower without
* correct alignment, for yet other it makes no difference.
* 对于视频，16或者32的倍数
* @note The linesize may be larger than the size of usable data -- there
* may be extra padding present for performance reasons.
* 出于性能原因，可能存在额外的填充
*/
int linesize[AV_NUM_DATA_POINTERS];
/**
* pointers to the data planes/channels.
*
* For video, this should simply point to data[].
*
* For planar audio, each channel has a separate data pointer, and
* linesize[0] contains the size of each channel buffer.
* For packed audio, there is just one data pointer, and linesize[0]
* contains the total size of the buffer for all channels.
*
* Note: Both data and extended_data should always be set in a valid frame,
* but for planar audio with more channels that can fit in data,
* extended_data must be used in order to access all channels.
* 对于需求更多通道的音频，必须使用extended_data
*/
uint8_t **extended_data;
/**
* @name Video dimensions
* Video frames only. The coded dimensions (in pixels) of the video frame,
* i.e. the size of the rectangle that contains some well-defined values.
*
* @note The part of the frame intended for display/presentation is further
* restricted by the @ref cropping "Cropping rectangle".
* @{
* 视频参数
*/
int width, height;
/**
* @}
*/
/**
* number of audio samples (per channel) described by this frame
* 音频参数
*/
int nb_samples;
/**
* format of the frame, -1 if unknown or unset
* Values correspond to enum AVPixelFormat for video frames,
* enum AVSampleFormat for audio)
* 未知或者未设置则为-1
* 音频的AVSampleForamt，视频的AVPixelFormat
*/
int format;
/**
* 1 -> keyframe, 0-> not
* 关键帧
*/
int key_frame;
/**
* Picture type of the frame.
*/
enum AVPictureType pict_type;
/**
* Sample aspect ratio for the video frame, 0/1 if unknown/unspecified.
*/
AVRational sample_aspect_ratio;
/**
* Presentation timestamp in time_base units (time when frame should be shown to user).
*/
int64_t pts;
#if FF_API_PKT_PTS
/**
* PTS copied from the AVPacket that was decoded to produce this frame.
* @deprecated use the pts field instead
*/
attribute_deprecated
int64_t pkt_pts; // 不再使用
#endif
/**
* DTS copied from the AVPacket that triggered returning this frame. (if frame threading isn't used)
* This is also the Presentation time of this AVFrame calculated from
* only AVPacket.dts values without pts values.
*/
int64_t pkt_dts;
/**
* picture number in bitstream order
* 解码后index， 0I 3B 2B 4B 5P
*/
int coded_picture_number;
/**
* picture number in display order
*/
int display_picture_number;
/**
* quality (between 1 (good) and FF_LAMBDA_MAX (bad))
*/
int quality;
/**
* for some private data of the user
*/
void *opaque;
#if FF_API_ERROR_FRAME
/**
* @deprecated unused
*/
attribute_deprecated
uint64_t error[AV_NUM_DATA_POINTERS];
#endif
/**
* When decoding, this signals how much the picture must be delayed.
* extra_delay = repeat_pict / (2*fps)
*/
int repeat_pict;
/**
* The content of the picture is interlaced.
*/
int interlaced_frame;
/**
* If the content is interlaced, is top field displayed first.
*/
int top_field_first;
/**
* Tell user application that palette has changed from previous frame.
*/
int palette_has_changed;
/**
* reordered opaque 64 bits (generally an integer or a double precision float
* PTS but can be anything).
* The user sets AVCodecContext.reordered_opaque to represent the input at
* that time,
* the decoder reorders values as needed and sets AVFrame.reordered_opaque
* to exactly one of the values provided by the user through AVCodecContext.reordered_opaque
*/
int64_t reordered_opaque;
/**
* Sample rate of the audio data.
* 音频采样率
*/
int sample_rate;
/**
* Channel layout of the audio data.
* 量化格式
*/
uint64_t channel_layout;
/**
* AVBuffer references backing the data for this frame. If all elements of
* this array are NULL, then this frame is not reference counted. This array
* must be filled contiguously -- if buf[i] is non-NULL then buf[j] must
* also be non-NULL for all j < i.
*
* There may be at most one AVBuffer per data plane, so for video this array
* always contains all the references. For planar audio with more than
* AV_NUM_DATA_POINTERS channels, there may be more buffers than can fit in
* this array. Then the extra AVBufferRef pointers are stored in the
* extended_buf array.
* 同data
*/
AVBufferRef *buf[AV_NUM_DATA_POINTERS];
/**
* For planar audio which requires more than AV_NUM_DATA_POINTERS
* AVBufferRef pointers, this array will hold all the references which
* cannot fit into AVFrame.buf.
*
* Note that this is different from AVFrame.extended_data, which always
* contains all the pointers. This array only contains the extra pointers,
* which cannot fit into AVFrame.buf.
*
* This array is always allocated using av_malloc() by whoever constructs
* the frame. It is freed in av_frame_unref().
* 同extended_data
*/
AVBufferRef **extended_buf;
/**
* Number of elements in extended_buf.
*/
int nb_extended_buf;
AVFrameSideData **side_data;
int nb_side_data;
/**
* @defgroup lavu_frame_flags AV_FRAME_FLAGS
* @ingroup lavu_frame
* Flags describing additional frame properties.
*
* @{
*/
/**
* The frame data may be corrupted, e.g. due to decoding errors.
*/
#define AV_FRAME_FLAG_CORRUPT (1 << 0)
/**
* A flag to mark the frames which need to be decoded, but shouldn't be output.
*/
#define AV_FRAME_FLAG_DISCARD (1 << 2)
/**
* @}
*/
/**
* Frame flags, a combination of @ref lavu_frame_flags
*/
int flags;
/**
* MPEG vs JPEG YUV range.
* - encoding: Set by user
* - decoding: Set by libavcodec
*/
enum AVColorRange color_range;
enum AVColorPrimaries color_primaries;
enum AVColorTransferCharacteristic color_trc;
/**
* YUV colorspace type.
* - encoding: Set by user
* - decoding: Set by libavcodec
*/
enum AVColorSpace colorspace;
enum AVChromaLocation chroma_location;
/**
* frame timestamp estimated using various heuristics, in stream time base
* - encoding: unused
* - decoding: set by libavcodec, read by user.
*/
int64_t best_effort_timestamp;
/**
* reordered pos from the last AVPacket that has been input into the decoder
* - encoding: unused
* - decoding: Read by user.
*/
int64_t pkt_pos;
/**
* duration of the corresponding packet, expressed in
* AVStream->time_base units, 0 if unknown.
* - encoding: unused
* - decoding: Read by user.
*/
int64_t pkt_duration;
/**
* metadata.
* - encoding: Set by user.
* - decoding: Set by libavcodec.
*/
AVDictionary *metadata;
/**
* decode error flags of the frame, set to a combination of
* FF_DECODE_ERROR_xxx flags if the decoder produced a frame, but there
* were errors during the decoding.
* - encoding: unused
* - decoding: set by libavcodec, read by user.
*/
int decode_error_flags;
#define FF_DECODE_ERROR_INVALID_BITSTREAM 1
#define FF_DECODE_ERROR_MISSING_REFERENCE 2
#define FF_DECODE_ERROR_CONCEALMENT_ACTIVE 4
#define FF_DECODE_ERROR_DECODE_SLICES 8
/**
* number of audio channels, only used for audio.
* - encoding: unused
* - decoding: Read by user.
* 通道数
*/
int channels;
/**
* size of the corresponding packet containing the compressed
* frame.
* It is set to a negative value if unknown.
* - encoding: unused
* - decoding: set by libavcodec, read by user.
* 此Frame的数据长度
*/
int pkt_size;
#if FF_API_FRAME_QP
/**
* QP table
*/
attribute_deprecated
int8_t *qscale_table;
/**
* QP store stride
*/
attribute_deprecated
int qstride;
attribute_deprecated
int qscale_type;
attribute_deprecated
AVBufferRef *qp_table_buf;
#endif
/**
* For hwaccel-format frames, this should be a reference to the
* AVHWFramesContext describing the frame.
*/
AVBufferRef *hw_frames_ctx;
/**
* AVBufferRef for free use by the API user. FFmpeg will never check the
* contents of the buffer ref. FFmpeg calls av_buffer_unref() on it when
* the frame is unreferenced. av_frame_copy_props() calls create a new
* reference with av_buffer_ref() for the target frame's opaque_ref field.
*
* This is unrelated to the opaque field, although it serves a similar
* purpose.
*/
AVBufferRef *opaque_ref;
/**
* @anchor cropping
* @name Cropping
* Video frames only. The number of pixels to discard from the the
* top/bottom/left/right border of the frame to obtain the sub-rectangle of
* the frame intended for presentation.
* @{
*/
size_t crop_top;
size_t crop_bottom;
size_t crop_left;
size_t crop_right;
/**
* @}
*/
/**
* AVBufferRef for internal use by a single libav* library.
* Must not be used to transfer data between libraries.
* Has to be NULL when ownership of the frame leaves the respective library.
*
* Code outside the FFmpeg libs should never check or change the contents of the buffer ref.
*
* FFmpeg calls av_buffer_unref() on it when the frame is unreferenced.
* av_frame_copy_props() calls create a new reference with av_buffer_ref()
* for the target frame's private_ref field.
*/
AVBufferRef *private_ref;
} AVFrame;
/**
* @}
* @}
* @defgroup lavu_picture Image related
*
* AVPicture types, pixel formats and basic image planes manipulation.
*
* @{
*/
enum AVPictureType {
AV_PICTURE_TYPE_NONE = 0, ///< Undefined
AV_PICTURE_TYPE_I, ///< Intra
AV_PICTURE_TYPE_P, ///< Predicted
AV_PICTURE_TYPE_B, ///< Bi-dir predicted
AV_PICTURE_TYPE_S, ///< S(GMC)-VOP MPEG-4
AV_PICTURE_TYPE_SI, ///< Switching Intra
AV_PICTURE_TYPE_SP, ///< Switching Predicted
AV_PICTURE_TYPE_BI, ///< BI type
};
相关函数
av_frame_alloc
/**
* Allocate an AVFrame and set its fields to default values. The resulting
* struct must be freed using av_frame_free().
*
* @return An AVFrame filled with default values or NULL on failure.
*
* @note this only allocates the AVFrame itself, not the data buffers. Those
* must be allocated through other means, e.g. with av_frame_get_buffer() or
* manually.
*/
AVFrame *av_frame_alloc(void)
{
AVFrame *frame = av_mallocz(sizeof(*frame));
if (!frame)
return NULL;
frame->extended_data = NULL;
get_frame_defaults(frame);
return frame;
}
av_frame_free
/**
* Free the frame and any dynamically allocated objects in it,
* e.g. extended_data. If the frame is reference counted, it will be
* unreferenced first.
*
* @param frame frame to be freed. The pointer will be set to NULL.
*/
void av_frame_free(AVFrame **frame)
{
if (!frame || !*frame)
return;
av_frame_unref(*frame);
av_freep(frame);
}
av_framme_ref
/**
* Set up a new reference to the data described by the source frame.
*
* Copy frame properties from src to dst and create a new reference for each
* AVBufferRef from src.
*
* If src is not reference counted, new buffers are allocated and the data is
* copied.
*
* @warning: dst MUST have been either unreferenced with av_frame_unref(dst),
* or newly allocated with av_frame_alloc() before calling this
* function, or undefined behavior will occur.
*
* @return 0 on success, a negative AVERROR on error
*/
int av_frame_ref(AVFrame *dst, const AVFrame *src)
{
int i, ret = 0;
av_assert1(dst->width == 0 && dst->height == 0);
av_assert1(dst->channels == 0);
dst->format = src->format;
dst->width = src->width;
dst->height = src->height;
dst->channels = src->channels;
dst->channel_layout = src->channel_layout;
dst->nb_samples = src->nb_samples;
ret = frame_copy_props(dst, src, 0);
if (ret < 0)
return ret;
/* duplicate the frame data if it's not refcounted */
if (!src->buf[0]) {
ret = av_frame_get_buffer(dst, 32);
if (ret < 0)
return ret;
ret = av_frame_copy(dst, src);
if (ret < 0)
av_frame_unref(dst);
return ret;
}
/* ref the buffers */
for (i = 0; i < FF_ARRAY_ELEMS(src->buf); i++) {
if (!src->buf[i])
continue;
dst->buf[i] = av_buffer_ref(src->buf[i]);
if (!dst->buf[i]) {
ret = AVERROR(ENOMEM);
goto fail;
}
}
if (src->extended_buf) {
dst->extended_buf = av_mallocz_array(sizeof(*dst->extended_buf),
src->nb_extended_buf);
if (!dst->extended_buf) {
ret = AVERROR(ENOMEM);
goto fail;
}
dst->nb_extended_buf = src->nb_extended_buf;
for (i = 0; i < src->nb_extended_buf; i++) {
dst->extended_buf[i] = av_buffer_ref(src->extended_buf[i]);
if (!dst->extended_buf[i]) {
ret = AVERROR(ENOMEM);
goto fail;
}
}
}
if (src->hw_frames_ctx) {
dst->hw_frames_ctx = av_buffer_ref(src->hw_frames_ctx);
if (!dst->hw_frames_ctx) {
ret = AVERROR(ENOMEM);
goto fail;
}
}
/* duplicate extended data */
if (src->extended_data != src->data) {
int ch = src->channels;
if (!ch) {
ret = AVERROR(EINVAL);
goto fail;
}
CHECK_CHANNELS_CONSISTENCY(src);
dst->extended_data = av_malloc_array(sizeof(*dst->extended_data), ch);
if (!dst->extended_data) {
ret = AVERROR(ENOMEM);
goto fail;
}
memcpy(dst->extended_data, src->extended_data, sizeof(*src->extended_data) * ch);
} else
dst->extended_data = dst->data;
memcpy(dst->data, src->data, sizeof(src->data));
memcpy(dst->linesize, src->linesize, sizeof(src->linesize));
return 0;
fail:
av_frame_unref(dst);
return ret;
}
av_frame_unref
/**
* Unreference all the buffers referenced by frame and reset the frame fields.
*/
void av_frame_unref(AVFrame *frame)
{
int i;
if (!frame)
return;
wipe_side_data(frame);
for (i = 0; i < FF_ARRAY_ELEMS(frame->buf); i++)
av_buffer_unref(&frame->buf[i]);
for (i = 0; i < frame->nb_extended_buf; i++)
av_buffer_unref(&frame->extended_buf[i]);
av_freep(&frame->extended_buf);
av_dict_free(&frame->metadata);
#if FF_API_FRAME_QP
FF_DISABLE_DEPRECATION_WARNINGS
av_buffer_unref(&frame->qp_table_buf);
FF_ENABLE_DEPRECATION_WARNINGS
#endif
av_buffer_unref(&frame->hw_frames_ctx);
av_buffer_unref(&frame->opaque_ref);
av_buffer_unref(&frame->private_ref);
get_frame_defaults(frame);
}
static void get_frame_defaults(AVFrame *frame)
{
if (frame->extended_data != frame->data)
av_freep(&frame->extended_data);
memset(frame, 0, sizeof(*frame));
frame->pts =
frame->pkt_dts = AV_NOPTS_VALUE;
#if FF_API_PKT_PTS
FF_DISABLE_DEPRECATION_WARNINGS
frame->pkt_pts = AV_NOPTS_VALUE;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
frame->best_effort_timestamp = AV_NOPTS_VALUE;
frame->pkt_duration = 0;
frame->pkt_pos = -1;
frame->pkt_size = -1;
frame->key_frame = 1;
frame->sample_aspect_ratio = (AVRational){ 0, 1 };
frame->format = -1; /* unknown */
frame->extended_data = frame->data;
frame->color_primaries = AVCOL_PRI_UNSPECIFIED;
frame->color_trc = AVCOL_TRC_UNSPECIFIED;
frame->colorspace = AVCOL_SPC_UNSPECIFIED;
frame->color_range = AVCOL_RANGE_UNSPECIFIED;
frame->chroma_location = AVCHROMA_LOC_UNSPECIFIED;
frame->flags = 0;
}
av_frame_move_ref
/**
* Move everything contained in src to dst and reset src.
*
* @warning: dst is not unreferenced, but directly overwritten without reading
* or deallocating its contents. Call av_frame_unref(dst) manually
* before calling this function to ensure that no memory is leaked.
*/
void av_frame_move_ref(AVFrame *dst, AVFrame *src)
{
av_assert1(dst->width == 0 && dst->height == 0);
av_assert1(dst->channels == 0);
*dst = *src;
if (src->extended_data == src->data)
dst->extended_data = dst->data;
memset(src, 0, sizeof(*src));
get_frame_defaults(src);
}
av_frame_clone
/**
* Create a new frame that references the same data as src.
*
* This is a shortcut for av_frame_alloc()+av_frame_ref().
*
* @return newly created AVFrame on success, NULL on error.
*/
AVFrame *av_frame_clone(const AVFrame *src)
{
AVFrame *ret = av_frame_alloc();
if (!ret)
return NULL;
if (av_frame_ref(ret, src) < 0)
av_frame_free(&ret);
return ret;
}
av_frame_is_writable
/**
* Check if the frame data is writable.
*
* @return A positive value if the frame data is writable (which is true if and
* only if each of the underlying buffers has only one reference, namely the one
* stored in this frame). Return 0 otherwise.
*
* If 1 is returned the answer is valid until av_buffer_ref() is called on any
* of the underlying AVBufferRefs (e.g. through av_frame_ref() or directly).
*
* @see av_frame_make_writable(), av_buffer_is_writable()
*/
int av_frame_is_writable(AVFrame *frame)
{
int i, ret = 1;
/* assume non-refcounted frames are not writable */
if (!frame->buf[0])
return 0;
for (i = 0; i < FF_ARRAY_ELEMS(frame->buf); i++)
if (frame->buf[i])
ret &= !!av_buffer_is_writable(frame->buf[i]);
for (i = 0; i < frame->nb_extended_buf; i++)
ret &= !!av_buffer_is_writable(frame->extended_buf[i]);
return ret;
}
av_frame_make_writable
/**
* Ensure that the frame data is writable, avoiding data copy if possible.
*
* Do nothing if the frame is writable, allocate new buffers and copy the data
* if it is not.
*
* @return 0 on success, a negative AVERROR on error.
*
* @see av_frame_is_writable(), av_buffer_is_writable(),
* av_buffer_make_writable()
*/
int av_frame_make_writable(AVFrame *frame)
{
AVFrame tmp;
int ret;
if (!frame->buf[0])
return AVERROR(EINVAL);
if (av_frame_is_writable(frame))
return 0;
memset(&tmp, 0, sizeof(tmp));
tmp.format = frame->format;
tmp.width = frame->width;
tmp.height = frame->height;
tmp.channels = frame->channels;
tmp.channel_layout = frame->channel_layout;
tmp.nb_samples = frame->nb_samples;
ret = av_frame_get_buffer(&tmp, 32);
if (ret < 0)
return ret;
ret = av_frame_copy(&tmp, frame);
if (ret < 0) {
av_frame_unref(&tmp);
return ret;
}
ret = av_frame_copy_props(&tmp, frame);
if (ret < 0) {
av_frame_unref(&tmp);
return ret;
}
av_frame_unref(frame);
*frame = tmp;
if (tmp.data == tmp.extended_data)
frame->extended_data = frame->data;
return 0;
}
av_frame_get_buffer
/**
* Allocate new buffer(s) for audio or video data.
*
* The following fields must be set on frame before calling this function:
* - format (pixel format for video, sample format for audio)
* - width and height for video
* - nb_samples and channel_layout for audio
*
* This function will fill AVFrame.data and AVFrame.buf arrays and, if
* necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
* For planar formats, one buffer will be allocated for each plane.
*
* @warning: if frame already has been allocated, calling this function will
* leak memory. In addition, undefined behavior can occur in certain
* cases.
*
* @param frame frame in which to store the new buffers.
* @param align Required buffer size alignment. If equal to 0, alignment will be
* chosen automatically for the current CPU. It is highly
* recommended to pass 0 here unless you know what you are doing.
*
* @return 0 on success, a negative AVERROR on error.
*/
int av_frame_get_buffer(AVFrame *frame, int align)
{
if (frame->format < 0)
return AVERROR(EINVAL);
if (frame->width > 0 && frame->height > 0)
return get_video_buffer(frame, align);
else if (frame->nb_samples > 0 && (frame->channel_layout || frame->channels > 0))
return get_audio_buffer(frame, align);
return AVERROR(EINVAL);
}
static int get_video_buffer(AVFrame *frame, int align)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);
int ret, i, padded_height;
int plane_padding = FFMAX(16 + 16/*STRIDE_ALIGN*/, align);
if (!desc)
return AVERROR(EINVAL);
if ((ret = av_image_check_size(frame->width, frame->height, 0, NULL)) < 0)
return ret;
if (!frame->linesize[0]) {
if (align <= 0)
align = 32; /* STRIDE_ALIGN. Should be av_cpu_max_align() */
for(i=1; i<=align; i+=i) {
ret = av_image_fill_linesizes(frame->linesize, frame->format,
FFALIGN(frame->width, i));
if (ret < 0)
return ret;
if (!(frame->linesize[0] & (align-1)))
break;
}
for (i = 0; i < 4 && frame->linesize[i]; i++)
frame->linesize[i] = FFALIGN(frame->linesize[i], align);
}
padded_height = FFALIGN(frame->height, 32);
if ((ret = av_image_fill_pointers(frame->data, frame->format, padded_height,
NULL, frame->linesize)) < 0)
return ret;
frame->buf[0] = av_buffer_alloc(ret + 4*plane_padding);
if (!frame->buf[0]) {
ret = AVERROR(ENOMEM);
goto fail;
}
if ((ret = av_image_fill_pointers(frame->data, frame->format, padded_height,
frame->buf[0]->data, frame->linesize)) < 0)
goto fail;
for (i = 1; i < 4; i++) {
if (frame->data[i])
frame->data[i] += i * plane_padding;
}
frame->extended_data = frame->data;
return 0;
fail:
av_frame_unref(frame);
return ret;
}
static int get_audio_buffer(AVFrame *frame, int align)
{
int channels;
int planar = av_sample_fmt_is_planar(frame->format);
int planes;
int ret, i;
if (!frame->channels)
frame->channels = av_get_channel_layout_nb_channels(frame->channel_layout);
channels = frame->channels;
planes = planar ? channels : 1;
CHECK_CHANNELS_CONSISTENCY(frame);
if (!frame->linesize[0]) {
ret = av_samples_get_buffer_size(&frame->linesize[0], channels,
frame->nb_samples, frame->format,
align);
if (ret < 0)
return ret;
}
if (planes > AV_NUM_DATA_POINTERS) {
frame->extended_data = av_mallocz_array(planes,
sizeof(*frame->extended_data));
frame->extended_buf = av_mallocz_array((planes - AV_NUM_DATA_POINTERS),
sizeof(*frame->extended_buf));
if (!frame->extended_data || !frame->extended_buf) {
av_freep(&frame->extended_data);
av_freep(&frame->extended_buf);
return AVERROR(ENOMEM);
}
frame->nb_extended_buf = planes - AV_NUM_DATA_POINTERS;
} else
frame->extended_data = frame->data;
for (i = 0; i < FFMIN(planes, AV_NUM_DATA_POINTERS); i++) {
frame->buf[i] = av_buffer_alloc(frame->linesize[0]);
if (!frame->buf[i]) {
av_frame_unref(frame);
return AVERROR(ENOMEM);
}
frame->extended_data[i] = frame->data[i] = frame->buf[i]->data;
}
for (i = 0; i < planes - AV_NUM_DATA_POINTERS; i++) {
frame->extended_buf[i] = av_buffer_alloc(frame->linesize[0]);
if (!frame->extended_buf[i]) {
av_frame_unref(frame);
return AVERROR(ENOMEM);
}
frame->extended_data[i + AV_NUM_DATA_POINTERS] = frame->extended_buf[i]->data;
}
return 0;
}
av_frame_get_planar_buffer
/**
* Get the buffer reference a given data plane is stored in.
*
* @param plane index of the data plane of interest in frame->extended_data.
*
* @return the buffer reference that contains the plane or NULL if the input
* frame is not valid.
*/
AVBufferRef *av_frame_get_plane_buffer(AVFrame *frame, int plane)
{
uint8_t *data;
int planes, i;
if (frame->nb_samples) {
int channels = frame->channels;
if (!channels)
return NULL;
CHECK_CHANNELS_CONSISTENCY(frame);
planes = av_sample_fmt_is_planar(frame->format) ? channels : 1;
} else
planes = 4;
if (plane < 0 || plane >= planes || !frame->extended_data[plane])
return NULL;
data = frame->extended_data[plane];
for (i = 0; i < FF_ARRAY_ELEMS(frame->buf) && frame->buf[i]; i++) {
AVBufferRef *buf = frame->buf[i];
if (data >= buf->data && data < buf->data + buf->size)
return buf;
}
for (i = 0; i < frame->nb_extended_buf; i++) {
AVBufferRef *buf = frame->extended_buf[i];
if (data >= buf->data && data < buf->data + buf->size)
return buf;
}
return NULL;
}
frame_copy_video
static int frame_copy_video(AVFrame *dst, const AVFrame *src)
{
const uint8_t *src_data[4];
int i, planes;
if (dst->width < src->width ||
dst->height < src->height)
return AVERROR(EINVAL);
planes = av_pix_fmt_count_planes(dst->format);
for (i = 0; i < planes; i++)
if (!dst->data[i] || !src->data[i])
return AVERROR(EINVAL);
memcpy(src_data, src->data, sizeof(src_data));
av_image_copy(dst->data, dst->linesize,
src_data, src->linesize,
dst->format, src->width, src->height);
return 0;
}
frame_copy_audio
static int frame_copy_audio(AVFrame *dst, const AVFrame *src)
{
int planar = av_sample_fmt_is_planar(dst->format);
int channels = dst->channels;
int planes = planar ? channels : 1;
int i;
if (dst->nb_samples != src->nb_samples ||
dst->channels != src->channels ||
dst->channel_layout != src->channel_layout)
return AVERROR(EINVAL);
CHECK_CHANNELS_CONSISTENCY(src);
for (i = 0; i < planes; i++)
if (!dst->extended_data[i] || !src->extended_data[i])
return AVERROR(EINVAL);
av_samples_copy(dst->extended_data, src->extended_data, 0, 0,
dst->nb_samples, channels, dst->format);
return 0;
}
本文来自博客园，作者：flxx，转载请注明原文链接：https://www.cnblogs.com/faithlocus/p/15636173.html
